diff --git a/lib/feed-v1/index.js b/lib/feed-v1/index.js
index a27329f..bc63d7c 100644
--- a/lib/feed-v1/index.js
+++ b/lib/feed-v1/index.js
@@ -12,9 +12,7 @@ const {
   validateType,
   validateContent,
   validate,
-  validateOOO,
   validateBatch,
-  validateOOOBatch,
   validateMsgHash,
 } = require('./validation')
 
@@ -23,7 +21,7 @@ const {
  */
 
 /**
- * @typedef {Object} TangleData
+ * @typedef {Object} TangleMetadata
  * @property {number} depth
  * @property {Array<string>} prev
  */
@@ -32,80 +30,73 @@ const {
  * @typedef {Object} Msg
  * @property {*} content
  * @property {Object} metadata
- * @property {number} metadata.depth
- * @property {Array<string>} metadata.prev
  * @property {string} metadata.proof
  * @property {number} metadata.size
- * @property {Record<string, TangleData>=} metadata.tangles
- * @property {string=} metadata.type
+ * @property {Record<string, TangleMetadata>} metadata.tangles
+ * @property {string} metadata.type
  * @property {string} metadata.who
- * @property {number=} metadata.when
+ * @property {number} metadata.when
  * @property {string} sig
  */
 
+/**
+ * @typedef {Object} Keys
+ * @property {string} keys.id
+ * @property {string} keys.private
+ */
+
 /**
  * @typedef {Object} CreateOpts
  * @property {*} content
  * @property {string} type
  * @property {number} when
- * @property {Object} keys
+ * @property {Keys} keys
+ * @property {Record<string, MsgIter>} tangles
+ */
+
+/**
+ * @typedef {Object} CreateRootOpts
+ * @property {string} type
+ * @property {Keys} keys
  * @property {string} keys.id
  * @property {string} keys.private
- * @property {MsgIter} existing
- * @property {Record<string, MsgIter>=} tangles
  */
 
 /**
  * @param {Msg} msg
  */
-function getFeedId(msg) {
-  if (msg.metadata.type) {
-    return `ppppp:feed/v1/${msg.metadata.who}/${msg.metadata.type}`
-  } else {
-    return `ppppp:feed/v1/${msg.metadata.who}`
-  }
-}
+// function getFeedId(msg) {
+//   if (msg.metadata.type) {
+//     return `ppppp:feed/v1/${msg.metadata.who}/${msg.metadata.type}`
+//   } else {
+//     return `ppppp:feed/v1/${msg.metadata.who}`
+//   }
+// }
 
-function isMsg(x) {
-  return (
-    typeof x === 'object' &&
-    !!x &&
-    typeof x.metadata.author === 'string' &&
-    x.metadata.author &&
-    typeof x.metadata.type === 'string' &&
-    x.metadata.type
-  )
-}
+// function isMsg(x) {
+//   return (
+//     typeof x === 'object' &&
+//     !!x &&
+//     typeof x.metadata.author === 'string' &&
+//     x.metadata.author &&
+//     typeof x.metadata.type === 'string' &&
+//     x.metadata.type
+//   )
+// }
 
-function isFeedId(author) {
-  if (typeof author !== 'string') return false
-  return author.startsWith('ppppp:feed/v1/')
-}
+// function isFeedId(author) {
+//   if (typeof author !== 'string') return false
+//   return author.startsWith('ppppp:feed/v1/')
+// }
 
 function toPlaintextBuffer(opts) {
   return Buffer.from(stringify(opts.content), 'utf8')
 }
 
-function readDepth(msg, tangleId = null) {
-  if (tangleId) {
-    return msg.metadata.tangles?.[tangleId]?.depth ?? 0
-  } else {
-    return msg.metadata.depth
-  }
-}
-
-function readPrev(msg, tangleId = null) {
-  if (tangleId) {
-    return msg.metadata.tangles?.[tangleId]?.prev ?? []
-  } else {
-    return msg.metadata.prev
-  }
-}
-
 function calculateDepth(existing, tangleId = null) {
   let max = -1
   for (const msg of existing.values()) {
-    const depth = readDepth(msg, tangleId)
+    const depth = msg.metadata.tangles[tangleId]?.depth ?? 0
     if (depth > max) {
       max = depth
     }
@@ -148,7 +139,7 @@ function determineTips(existing, tangleId = null) {
   }
 
   for (const msg of existing.values()) {
-    const prev = readPrev(msg, tangleId)
+    const prev = msg.metadata.tangles[tangleId]?.prev ?? []
     for (const p of prev) {
       tips.delete(p)
     }
@@ -160,7 +151,7 @@ function calculatePrev(existing, depth, lipmaaDepth, tangleId = null) {
   const prev = []
   const tips = determineTips(existing, tangleId)
   for (const msg of existing.values()) {
-    const msgDepth = readDepth(msg, tangleId)
+    const msgDepth = msg.metadata.tangles[tangleId]?.depth ?? 0
     const msgHash = getMsgHash(msg)
     if (
       msgDepth === depth - 1 ||
@@ -173,7 +164,12 @@ function calculatePrev(existing, depth, lipmaaDepth, tangleId = null) {
   return prev
 }
 
-function prevalidateExisting(existing, tangleId = null) {
+/**
+ * @param {MsgIter} existing
+ * @param {string} tangleId
+ * @returns
+ */
+function prevalidateExisting(existing, tangleId) {
   if (!existing?.[Symbol.iterator]) {
     // prettier-ignore
     return new Error(`existing must be an iterator, but got ${typeof existing}`)
@@ -182,6 +178,10 @@ function prevalidateExisting(existing, tangleId = null) {
     // prettier-ignore
     return new Error(`existing must be a Map, Set, or Array, but got ${existing}`)
   }
+  if (!tangleId) {
+    // prettier-ignore
+    return new Error(`tangleId must be a string, but got ${typeof tangleId}`)
+  }
   let isEmpty = true
   let hasDepthZeroMsg = false
   for (const p of existing.values()) {
@@ -191,25 +191,16 @@ function prevalidateExisting(existing, tangleId = null) {
       return new Error(`existing must contain messages, but got ${typeof p}`)
     }
 
-    if (!tangleId && p.metadata.depth === 0) {
+    if (!p.metadata.tangles[tangleId] && getMsgHash(p) === tangleId) {
       if (hasDepthZeroMsg) {
         // prettier-ignore
         return new Error(`existing must contain only 1 message with depth 0`)
       } else {
         hasDepthZeroMsg = true
       }
-    } else if (tangleId) {
-      if (!p.metadata.tangles?.[tangleId] && getMsgHash(p) === tangleId) {
-        if (hasDepthZeroMsg) {
-          // prettier-ignore
-          return new Error(`existing must contain only 1 message with depth 0`)
-        } else {
-          hasDepthZeroMsg = true
-        }
-      } else if (!p.metadata.tangles?.[tangleId]) {
-        // prettier-ignore
-        return new Error(`existing must refer to the tangleId ${tangleId}`)
-      }
+    } else if (!p.metadata.tangles[tangleId]) {
+      // prettier-ignore
+      return new Error(`existing must refer to the tangleId ${tangleId}`)
     }
   }
   if (!isEmpty && !hasDepthZeroMsg) {
@@ -225,14 +216,11 @@ function prevalidateExisting(existing, tangleId = null) {
 function create(opts) {
   let err
   if ((err = validateType(opts.type))) throw err
-  if ((err = prevalidateExisting(opts.existing))) throw err
+  if (!opts.tangles) throw new Error('opts.tangles is required')
 
   const [proof, size] = representContent(opts.content)
-  const depth = calculateDepth(opts.existing)
-  const lipmaaDepth = lipmaa(depth + 1) - 1
-  const prev = calculatePrev(opts.existing, depth, lipmaaDepth)
 
-  let tangles = null
+  const tangles = {}
   if (opts.tangles) {
     for (const rootId in opts.tangles) {
       if ((err = validateMsgHash(rootId))) throw err
@@ -242,19 +230,19 @@ function create(opts) {
       const depth = calculateDepth(existing, rootId)
       const lipmaaDepth = lipmaa(depth + 1) - 1
       const prev = calculatePrev(existing, depth, lipmaaDepth, rootId)
-      tangles ??= {}
       tangles[rootId] = { depth, prev }
     }
+  } else {
+    // prettier-ignore
+    throw new Error(`cannot create msg without tangles, that's the case for createRoot()`)
   }
 
   const msg = {
     content: opts.content,
     metadata: {
-      depth,
-      prev,
       proof,
       size,
-      ...(tangles ? { tangles } : null),
+      tangles,
       type: opts.type,
       who: stripAuthor(opts.keys.id),
       when: +opts.when,
@@ -273,6 +261,38 @@ function create(opts) {
   return msg
 }
 
+/**
+ * @param {Keys} keys
+ * @param {string} type
+ * @returns {Msg}
+ */
+function createRoot(keys, type) {
+  let err
+  if ((err = validateType(type))) throw err
+
+  const msg = {
+    content: null,
+    metadata: {
+      proof: '',
+      size: 0,
+      tangles: {},
+      type,
+      who: stripAuthor(keys.id),
+      when: 0,
+    },
+    sig: '',
+  }
+
+  const privateKey = Buffer.from(keys.private, 'base64')
+  // TODO: add a label prefix to the metadata before signing
+  const metadataBuf = Buffer.from(stringify(msg.metadata), 'utf8')
+  // TODO: when signing, what's the point of a customizable hmac?
+  const sigBuf = ed25519.sign(privateKey, metadataBuf)
+  msg.sig = base58.encode(sigBuf)
+
+  return msg
+}
+
 /**
  * @param {Buffer} plaintextBuf
  * @param {Msg} msg
@@ -285,14 +305,14 @@ function fromPlaintextBuffer(plaintextBuf, msg) {
 module.exports = {
   getMsgHash,
   getMsgId,
-  getFeedId,
-  isFeedId,
-  isMsg,
+  // getFeedId,
+  // isFeedId,
+  // isMsg,
   create,
+  createRoot,
+  stripAuthor,
   toPlaintextBuffer,
   fromPlaintextBuffer,
   validate,
-  validateOOO,
   validateBatch,
-  validateOOOBatch,
 }
diff --git a/lib/feed-v1/validation.js b/lib/feed-v1/validation.js
index 5da915c..7bd0d28 100644
--- a/lib/feed-v1/validation.js
+++ b/lib/feed-v1/validation.js
@@ -12,11 +12,8 @@ function validateShape(msg) {
   if (typeof msg.metadata.who === 'undefined') {
     return new Error('invalid message: must have metadata.who')
   }
-  if (typeof msg.metadata.depth === 'undefined') {
-    return new Error('invalid message: must have metadata.depth')
-  }
-  if (typeof msg.metadata.prev === 'undefined') {
-    return new Error('invalid message: must have metadata.prev')
+  if (typeof msg.metadata.tangles !== 'object') {
+    return new Error('invalid message: must have metadata.tangles')
   }
   if (typeof msg.metadata.proof === 'undefined') {
     return new Error('invalid message: must have metadata.proof')
@@ -45,7 +42,9 @@ function validateMsgHash(str) {
   try {
     base58.decode(str)
   } catch (err) {
-    return new Error(`invalid message: msgHash ${str} should have been a base58 string`)
+    return new Error(
+      `invalid message: msgHash ${str} should have been a base58 string`
+    )
   }
 }
 
@@ -74,12 +73,13 @@ function validateSignature(msg) {
   }
 }
 
-function validatePrev(msg, existingMsgs) {
-  if (!msg.metadata.prev || !msg.metadata.prev[Symbol.iterator]) {
+function validateTangle(msg, existingMsgs, tangleId) {
+  const tangle = msg.metadata.tangles[tangleId]
+  if (!tangle?.prev || !Array.isArray(tangle.prev)) {
     // prettier-ignore
-    return new Error('invalid message: prev must be an iterator, on feed: ' + msg.metadata.who);
+    return new Error('invalid message: prev must be an array, on feed: ' + msg.metadata.who);
   }
-  for (const p of msg.metadata.prev) {
+  for (const p of tangle.prev) {
     if (typeof p !== 'string') {
       // prettier-ignore
       return new Error('invalid message: prev must contain strings but found ' + p + ', on feed: ' + msg.metadata.who);
@@ -103,21 +103,18 @@ function validatePrev(msg, existingMsgs) {
       // prettier-ignore
       return new Error('invalid message: prev ' + p + ' is not from the same type, on feed: ' + msg.metadata.who);
     }
-    if (existingMsg.metadata.depth >= msg.metadata.depth) {
+    const existingDepth = existingMsg.metadata.tangles[tangleId]?.depth ?? 0
+    if (existingDepth >= tangle.depth) {
       // prettier-ignore
       return new Error('invalid message: depth of prev ' + p + ' is not lower, on feed: ' + msg.metadata.who);
     }
   }
 }
 
-function validateFirstPrev(msg) {
-  if (!Array.isArray(msg.metadata.prev)) {
+function validateTangleRoot(msg, tangleId) {
+  if (msg.metadata.tangles[tangleId]) {
     // prettier-ignore
-    return new Error('invalid message: prev must be an array, on feed: ' + msg.metadata.who);
-  }
-  if (msg.metadata.prev.length !== 0) {
-    // prettier-ignore
-    return new Error('invalid message: prev of 1st msg must be an empty array, on feed: ' + msg.metadata.who);
+    return new Error('invalid message: tangle root must not have self tangle data, on feed: ' + msg.metadata.who);
   }
 }
 
@@ -152,7 +149,7 @@ function validateContent(msg) {
   // FIXME: if content does not exist, do nothing
   const { content } = msg
   if (!content) {
-    return new Error('invalid message: must have content')
+    return
   }
   if (Array.isArray(content)) {
     return new Error('invalid message: content must not be an array')
@@ -165,48 +162,28 @@ function validateContent(msg) {
 
 // FIXME: validateDepth should be +1 of the max of prev depth
 
-function validateSync(msg, existingMsgs) {
+function validateSync(msg, existingMsgs, msgHash, rootHash) {
   let err
   if ((err = validateShape(msg))) return err
   if ((err = validateWho(msg))) return err
   if ((err = validateWhen(msg))) return err
-  if (msg.metadata.depth === 0) {
-    if ((err = validateFirstPrev(msg))) return err
+  if (msgHash === rootHash) {
+    if ((err = validateTangleRoot(msg))) return err
   } else {
-    if ((err = validatePrev(msg, existingMsgs))) return err
+    if ((err = validateTangle(msg, existingMsgs, rootHash))) return err
   }
   if ((err = validateContent(msg))) return err
   if ((err = validateSignature(msg))) return err
 }
 
-// function validateOOOSync(nativeMsg, hmacKey) {
-//   let err
-//   if ((err = validateShape(nativeMsg))) return err
-//   if ((err = validateHmac(hmacKey))) return err
-//   if ((err = validateAuthor(nativeMsg))) return err
-//   if ((err = validateHash(nativeMsg))) return err
-//   if ((err = validateOrder(nativeMsg))) return err
-//   if ((err = validateContent(nativeMsg))) return err
-//   if ((err = validateAsJSON(nativeMsg))) return err
-//   if ((err = validateSignature(nativeMsg, hmacKey))) return err
-// }
-
-function validate(msg, existingMsgs, cb) {
+function validate(msg, existingMsgs, msgHash, rootHash, cb) {
   let err
-  if ((err = validateSync(msg, existingMsgs))) {
+  if ((err = validateSync(msg, existingMsgs, msgHash, rootHash))) {
     return cb(err)
   }
   cb()
 }
 
-// function validateOOO(nativeMsg, hmacKey, cb) {
-//   let err
-//   if ((err = validateOOOSync(nativeMsg, hmacKey))) {
-//     return cb(err)
-//   }
-//   cb()
-// }
-
 // function validateBatch(nativeMsgs, prevNativeMsg, hmacKey, cb) {
 //   let err
 //   let prev = prevNativeMsg
@@ -218,15 +195,6 @@ function validate(msg, existingMsgs, cb) {
 //   cb()
 // }
 
-// function validateOOOBatch(nativeMsgs, hmacKey, cb) {
-//   let err
-//   for (const nativeMsg of nativeMsgs) {
-//     err = validateOOOSync(nativeMsg, hmacKey)
-//     if (err) return cb(err)
-//   }
-//   cb()
-// }
-
 module.exports = {
   validateType,
   validateContent,
@@ -234,6 +202,4 @@ module.exports = {
   validate,
   validateMsgHash,
   // validateBatch,
-  // validateOOO,
-  // validateOOOBatch,
 }
diff --git a/lib/plugin.js b/lib/plugin.js
index 6890edb..e171236 100644
--- a/lib/plugin.js
+++ b/lib/plugin.js
@@ -4,7 +4,7 @@ const AAOL = require('async-append-only-log')
 const promisify = require('promisify-4loc')
 const Obz = require('obz')
 const FeedV1 = require('./feed-v1')
-const { ReadyGate } = require('./utils')
+const { ReadyGate, isEmptyObject } = require('./utils')
 const { decrypt } = require('./encryption')
 
 /**
@@ -48,33 +48,6 @@ exports.init = function initDB(peer, config) {
   const encryptionFormats = new Map()
   const onRecordAdded = Obz()
 
-  const msgsPerFeed = {
-    _mapAll: new Map(), // who => Set<MsgHash>
-    _byHash: new Map(), // msgId => Msg // TODO: optimize space usage of this??
-    update(msg, msgHash) {
-      const feedId = FeedV1.getFeedId(msg)
-      const setAll = this._mapAll.get(feedId) ?? new Set()
-      setAll.add(msgHash)
-      this._mapAll.set(feedId, setAll)
-      this._byHash.set(msgHash, msg)
-    },
-    getAll(feedId) {
-      const map = new Map()
-      for (const msgHash of this._mapAll.get(feedId) ?? []) {
-        const msg = this._byHash.get(msgHash)
-        if (msg) map.set(msgHash, msg)
-      }
-      return map
-    },
-    deleteMsg(msg) {
-      const feedId = FeedV1.getFeedId(msg)
-      const msgHash = FeedV1.getMsgHash(msg)
-      const setAll = this._mapAll.get(feedId)
-      setAll.delete(msgHash)
-      this._byHash.delete(msgHash)
-    },
-  }
-
   const log = AAOL(path.join(config.path, 'db.bin'), {
     cacheSize: 1,
     blockSize: 64 * 1024,
@@ -124,8 +97,6 @@ exports.init = function initDB(peer, config) {
           rec.misc.size = size
           rec.misc.seq = i
           recs.push(rec)
-
-          msgsPerFeed.update(rec.msg)
         },
         function drainEnd(err) {
           // prettier-ignore
@@ -175,20 +146,17 @@ exports.init = function initDB(peer, config) {
     return encryptionFormat
   }
 
-  function add(msg, cb) {
-    const feedId = FeedV1.getFeedId(msg)
+  function add(msg, tangleRootHash, cb) {
     // TODO: optimize this. This may be slow if you're adding many msgs in a
-    // row, because `getAll()` creates a new Map() each time.
-    const existingMsgs = msgsPerFeed.getAll(feedId)
+    // row, because it creates a new Map() each time.
+    const tangleMsgs = populateTangle(tangleRootHash)
 
-    FeedV1.validate(msg, existingMsgs, validationCB)
+    const msgHash = FeedV1.getMsgHash(msg)
+    FeedV1.validate(msg, tangleMsgs, msgHash, tangleRootHash, validationCB)
 
     function validationCB(err) {
       // prettier-ignore
       if (err) return cb(new Error('add() failed validation for feed format v1', {cause: err}))
-      const msgHash = FeedV1.getMsgHash(msg)
-      msgsPerFeed.update(msg, msgHash)
-
       logAppend(msgHash, msg, logAppendCB)
     }
 
@@ -199,6 +167,16 @@ exports.init = function initDB(peer, config) {
     }
   }
 
+  function getFeedRoot(findWho, findType) {
+    for (const rec of records()) {
+      const { who, type, tangles } = rec.msg.metadata
+      if (who === findWho && type === findType && isEmptyObject(tangles)) {
+        return rec.hash
+      }
+    }
+    return null
+  }
+
   function populateTangle(tangleId) {
     const map = new Map()
     for (const rec of records()) {
@@ -212,7 +190,7 @@ exports.init = function initDB(peer, config) {
   function populateTangles(tangleIds) {
     const tangles = {}
     for (const tangleId of tangleIds) {
-      tangles[tangleId] = populateTangle(tangleId)
+      tangles[tangleId] ??= populateTangle(tangleId)
     }
     return tangles
   }
@@ -230,23 +208,22 @@ exports.init = function initDB(peer, config) {
     if (!opts.content) return cb(new Error('create() requires a `content`'))
     if (!opts.type) return cb(new Error('create() requires a `type`'))
 
-    // Create full opts:
-    const tangles = populateTangles(opts.tangles ?? [])
-    let tempMsg
-    try {
-      tempMsg = FeedV1.create({
-        when: Date.now(),
-        ...opts,
-        tangles,
-        existing: [],
-        keys,
+    const feedRootHash = getFeedRoot(FeedV1.stripAuthor(keys.id), opts.type)
+    if (!feedRootHash) {
+      const feedRoot = FeedV1.createRoot(keys, opts.type)
+      add(feedRoot, FeedV1.getMsgHash(feedRoot), (err) => {
+        // prettier-ignore
+        if (err) return cb(new Error('create() failed to create root', {cause: err}));
+        create(opts, cb)
       })
-    } catch (err) {
-      return cb(new Error('create() failed', { cause: err }))
+      return
     }
-    const feedId = FeedV1.getFeedId(tempMsg)
-    const existing = msgsPerFeed.getAll(feedId)
-    const fullOpts = { when: Date.now(), ...opts, tangles, existing, keys }
+
+    // Fill-in tangle opts:
+    const tangleTemplates = opts.tangles ?? []
+    tangleTemplates.push(feedRootHash)
+    const tangles = populateTangles(tangleTemplates)
+    const fullOpts = { when: Date.now(), ...opts, tangles, keys }
 
     // If opts ask for encryption, encrypt and put ciphertext in opts.content
     const recps = fullOpts.content.recps
@@ -276,7 +253,6 @@ exports.init = function initDB(peer, config) {
       return cb(new Error('create() failed', { cause: err }))
     }
     const msgHash = FeedV1.getMsgHash(msg)
-    msgsPerFeed.update(msg, msgHash)
 
     // Encode the native message and append it to the log:
     logAppend(msgHash, msg, (err, rec) => {
@@ -289,7 +265,6 @@ exports.init = function initDB(peer, config) {
 
   function del(msgId, cb) {
     const rec = getRecord(msgId)
-    msgsPerFeed.deleteMsg(rec.msg)
     const { offset, size, seq } = rec.misc
     recs[rec.misc.seq] = { misc: { offset, size, seq } }
     log.onDrain(() => {
@@ -317,7 +292,7 @@ exports.init = function initDB(peer, config) {
       const rec = recs[i]
       if (!rec) continue
       if (isUri && msgId.endsWith(rec.hash)) return rec
-      else if (!isUri && rec.hash.endsWith(msgId)) return rec
+      else if (!isUri && rec.hash === msgId) return rec
     }
     return null
   }
diff --git a/lib/utils.js b/lib/utils.js
index 73aee3a..6d7ce5a 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -18,4 +18,12 @@ class ReadyGate {
   }
 }
 
-module.exports = { ReadyGate }
+  function isEmptyObject(obj) {
+    for (const _key in obj) {
+      return false
+    }
+    return true
+  }
+
+
+module.exports = { ReadyGate, isEmptyObject }
diff --git a/test/add.test.js b/test/add.test.js
index b1b9dfc..fe8abf7 100644
--- a/test/add.test.js
+++ b/test/add.test.js
@@ -20,15 +20,23 @@ test('add()', async (t) => {
 
   await peer.db.loaded()
 
+  const rootMsg = FeedV1.createRoot(keys, 'post')
+  const rootHash = FeedV1.getMsgHash(rootMsg)
+
+  const recRoot = await p(peer.db.add)(rootMsg, rootHash)
+  t.equals(recRoot.msg.metadata.when, 0, 'root msg added')
+
   const inputMsg = FeedV1.create({
     keys,
     when: 1514517067954,
     type: 'post',
     content: { text: 'This is the first post!' },
-    existing: [],
+    tangles: {
+      [rootHash]: new Map([[FeedV1.getMsgHash(rootMsg), rootMsg]]),
+    },
   })
 
-  const rec = await p(peer.db.add)(inputMsg)
+  const rec = await p(peer.db.add)(inputMsg, rootHash)
   t.equal(rec.msg.content.text, 'This is the first post!')
 
   await p(peer.close)(true)
diff --git a/test/create.test.js b/test/create.test.js
index 73fc1c0..6a70c11 100644
--- a/test/create.test.js
+++ b/test/create.test.js
@@ -23,6 +23,8 @@ test('setup', async (t) => {
   await peer.db.loaded()
 })
 
+const rootMsg = FeedV1.createRoot(keys, 'post')
+const rootHash = FeedV1.getMsgHash(rootMsg)
 let msgHash1
 let rec1
 let msgHash2
@@ -32,6 +34,17 @@ test('create()', async (t) => {
     content: { text: 'I am 1st post' },
   })
   t.equal(rec1.msg.content.text, 'I am 1st post', 'msg1 text correct')
+  t.equal(
+    rec1.msg.metadata.tangles[rootHash].depth,
+    1,
+    'msg1 tangle depth correct'
+  )
+  t.deepEquals(
+    rec1.msg.metadata.tangles[rootHash].prev,
+    [rootHash],
+    'msg1 tangle prev correct'
+  )
+
   msgHash1 = FeedV1.getMsgHash(rec1.msg)
 
   const rec2 = await p(peer.db.create)({
@@ -39,7 +52,16 @@ test('create()', async (t) => {
     content: { text: 'I am 2nd post' },
   })
   t.equal(rec2.msg.content.text, 'I am 2nd post', 'msg2 text correct')
-  t.deepEquals(rec2.msg.metadata.prev, [msgHash1], 'msg2 prev correct')
+  t.equal(
+    rec2.msg.metadata.tangles[rootHash].depth,
+    2,
+    'msg2 tangle depth correct'
+  )
+  t.deepEquals(
+    rec2.msg.metadata.tangles[rootHash].prev,
+    [msgHash1],
+    'msg2 tangle prev correct'
+  )
   msgHash2 = FeedV1.getMsgHash(rec2.msg)
 })
 
@@ -49,10 +71,15 @@ test('add() forked then create() merged', async (t) => {
     when: Date.now(),
     type: 'post',
     content: { text: '3rd post forked from 1st' },
-    existing: [rec1.msg],
+    tangles: {
+      [rootHash]: new Map([
+        [rootHash, rootMsg],
+        [rec1.hash, rec1.msg],
+      ]),
+    },
   })
 
-  const rec3 = await p(peer.db.add)(msg3)
+  const rec3 = await p(peer.db.add)(msg3, rootHash)
   const msgHash3 = FeedV1.getMsgHash(rec3.msg)
 
   const rec4 = await p(peer.db.create)({
@@ -61,9 +88,9 @@ test('add() forked then create() merged', async (t) => {
   })
   t.ok(rec4, '4th post created')
   t.deepEquals(
-    rec4.msg.metadata.prev,
-    [msgHash2, msgHash3],
-    'msg4 prev is msg2 and msg3'
+    rec4.msg.metadata.tangles[rootHash].prev,
+    [rootHash, msgHash2, msgHash3],
+    'msg4 prev is root, msg2 and msg3'
   )
 })
 
diff --git a/test/del.test.js b/test/del.test.js
index 2364e20..c1c827a 100644
--- a/test/del.test.js
+++ b/test/del.test.js
@@ -31,7 +31,7 @@ test('del', async (t) => {
 
   const before = []
   for (const msg of peer.db.msgs()) {
-    before.push(msg.content.text)
+    if (msg.content) before.push(msg.content.text)
   }
 
   t.deepEqual(before, ['m0', 'm1', 'm2', 'm3', 'm4'], 'msgs before the delete')
@@ -40,7 +40,7 @@ test('del', async (t) => {
 
   const after = []
   for (const msg of peer.db.msgs()) {
-    after.push(msg.content.text)
+    if (msg.content) after.push(msg.content.text)
   }
 
   t.deepEqual(after, ['m0', 'm1', 'm3', 'm4'], 'msgs after the delete')
@@ -78,7 +78,7 @@ test('del', async (t) => {
   })
 
   t.deepEqual(
-    persistedMsgs.map((msg) => msg.content.text),
+    persistedMsgs.filter((msg) => msg.content).map((msg) => msg.content.text),
     ['m0', 'm1', 'm3', 'm4'],
     'msgs in disk after the delete'
   )
diff --git a/test/feed-v1-create.test.js b/test/feed-v1-create.test.js
index 018ee75..a666b6d 100644
--- a/test/feed-v1-create.test.js
+++ b/test/feed-v1-create.test.js
@@ -2,6 +2,24 @@ const tape = require('tape')
 const FeedV1 = require('../lib/feed-v1')
 const { generateKeypair } = require('./util')
 
+let rootMsg = null
+let rootHash = null
+tape('FeedV1.createRoot()', (t) => {
+  const keys = generateKeypair('alice')
+  rootMsg = FeedV1.createRoot(keys, 'post')
+  t.equals(rootMsg.content, null, 'content')
+  t.equals(rootMsg.metadata.proof, '', 'proof')
+  t.equals(rootMsg.metadata.size, 0, 'size')
+  t.equals(rootMsg.metadata.type, 'post', 'type')
+  t.equals(rootMsg.metadata.who, FeedV1.stripAuthor(keys.id), 'who')
+  t.equals(rootMsg.metadata.when, 0, 'when')
+  t.deepEquals(rootMsg.metadata.tangles, {}, 'tangles')
+
+  rootHash = FeedV1.getMsgHash(rootMsg)
+  t.equals(rootHash, 'PpkBfa8C4sB8wHrqiNmHqe', 'root hash')
+  t.end()
+})
+
 tape('FeedV1.create()', (t) => {
   const keys = generateKeypair('alice')
   const content = { text: 'Hello world!' }
@@ -11,12 +29,14 @@ tape('FeedV1.create()', (t) => {
     keys,
     content,
     type: 'post',
-    existing: [],
+    tangles: {
+      [rootHash]: new Map([[rootHash, rootMsg]]),
+    },
     when,
   })
   t.deepEquals(
     Object.keys(msg1.metadata),
-    ['depth', 'prev', 'proof', 'size', 'type', 'who', 'when'],
+    ['proof', 'size', 'tangles', 'type', 'who', 'when'],
     'metadata fields'
   )
   t.equals(
@@ -25,16 +45,17 @@ tape('FeedV1.create()', (t) => {
     'metadata.who'
   )
   t.equals(msg1.metadata.type, 'post', 'metadata.type')
-  t.equals(msg1.metadata.depth, 0, 'metadata.depth')
-  t.deepEquals(msg1.metadata.prev, [], 'metadata.prev')
   t.deepEquals(msg1.metadata.proof, '9R7XmBhHF5ooPg34j9TQcz', 'metadata.proof')
+  t.deepEquals(Object.keys(msg1.metadata.tangles), [rootHash], 'tangles')
+  t.equals(msg1.metadata.tangles[rootHash].depth, 1, 'tangle depth')
+  t.deepEquals(msg1.metadata.tangles[rootHash].prev, [rootHash], 'tangle prev')
   t.deepEquals(msg1.metadata.size, 23, 'metadata.size')
   t.equals(typeof msg1.metadata.when, 'number', 'metadata.when')
   t.deepEqual(msg1.content, content, 'content is correct')
 
   console.log(msg1)
 
-  const msgHash1 = '9cYegpVpddoMSdvSf53dTH'
+  const msgHash1 = 'YWbEeMtcU4eNwF6uJVTrKE'
 
   t.equals(
     FeedV1.getMsgId(msg1),
@@ -49,12 +70,17 @@ tape('FeedV1.create()', (t) => {
     keys,
     content: content2,
     type: 'post',
-    existing: new Map([[msgHash1, msg1]]),
+    tangles: {
+      [rootHash]: new Map([
+        [rootHash, rootMsg],
+        [msgHash1, msg1],
+      ]),
+    },
     when: when + 1,
   })
   t.deepEquals(
     Object.keys(msg2.metadata),
-    ['depth', 'prev', 'proof', 'size', 'type', 'who', 'when'],
+    ['proof', 'size', 'tangles', 'type', 'who', 'when'],
     'metadata keys'
   )
   t.equals(
@@ -63,8 +89,9 @@ tape('FeedV1.create()', (t) => {
     'metadata.who'
   )
   t.equals(msg2.metadata.type, 'post', 'metadata.type')
-  t.equals(msg2.metadata.depth, 1, 'metadata.depth')
-  t.deepEquals(msg2.metadata.prev, [msgHash1], 'metadata.prev')
+  t.deepEquals(Object.keys(msg1.metadata.tangles), [rootHash], 'tangles')
+  t.equals(msg2.metadata.tangles[rootHash].depth, 2, 'tangle depth')
+  t.deepEquals(msg2.metadata.tangles[rootHash].prev, [msgHash1], 'tangle prev')
   t.deepEquals(msg2.metadata.proof, 'XuZEzH1Dhy1yuRMcviBBcN', 'metadata.proof')
   t.deepEquals(msg2.metadata.size, 21, 'metadata.size')
   t.equals(typeof msg2.metadata.when, 'number', 'metadata.when')
@@ -74,7 +101,7 @@ tape('FeedV1.create()', (t) => {
 
   t.deepEqual(
     FeedV1.getMsgId(msg2),
-    'ppppp:message/v1/4mjQ5aJu378cEu6TksRG3uXAiKFiwGjYQtWAjfVjDAJW/post/LEH1JVENvJgSpBBrVUwJx6',
+    'ppppp:message/v1/4mjQ5aJu378cEu6TksRG3uXAiKFiwGjYQtWAjfVjDAJW/post/R9XRXBL1ntSKRrrk86bhn8',
     'getMsgId'
   )
 
@@ -84,17 +111,23 @@ tape('FeedV1.create()', (t) => {
 tape('create() handles DAG tips correctly', (t) => {
   const keys = generateKeypair('alice')
   const when = 1652037377204
-  const existing = new Map()
+  const existing = new Map([[rootHash, rootMsg]])
 
   const msg1 = FeedV1.create({
     keys,
     content: { text: '1' },
     type: 'post',
-    existing: new Map(),
+    tangles: {
+      [rootHash]: existing,
+    },
     when: when + 1,
   })
   const msgHash1 = FeedV1.getMsgHash(msg1)
-  t.deepEquals(msg1.metadata.prev, [], 'msg1.prev is empty')
+  t.deepEquals(
+    msg1.metadata.tangles[rootHash].prev,
+    ['PpkBfa8C4sB8wHrqiNmHqe'],
+    'msg1.prev is root'
+  )
 
   existing.set(msgHash1, msg1)
 
@@ -102,20 +135,33 @@ tape('create() handles DAG tips correctly', (t) => {
     keys,
     content: { text: '2A' },
     type: 'post',
-    existing,
+    tangles: {
+      [rootHash]: existing,
+    },
     when: when + 2,
   })
-  t.deepEquals(msg2A.metadata.prev, [msgHash1], 'msg2A.prev is msg1')
+  t.deepEquals(
+    msg2A.metadata.tangles[rootHash].prev,
+    [msgHash1],
+    'msg2A.prev is msg1'
+  )
 
   const msg2B = FeedV1.create({
     keys,
     content: { text: '2B' },
     type: 'post',
+    tangles: {
+      [rootHash]: existing,
+    },
     existing,
     when: when + 2,
   })
   const msgHash2B = FeedV1.getMsgHash(msg2B)
-  t.deepEquals(msg2B.metadata.prev, [msgHash1], 'msg2B.prev is msg1')
+  t.deepEquals(
+    msg2B.metadata.tangles[rootHash].prev,
+    [msgHash1],
+    'msg2B.prev is msg1'
+  )
 
   existing.set(msgHash2B, msg2B)
 
@@ -123,11 +169,17 @@ tape('create() handles DAG tips correctly', (t) => {
     keys,
     content: { text: '3' },
     type: 'post',
-    existing,
+    tangles: {
+      [rootHash]: existing,
+    },
     when: when + 3,
   })
   const msgHash3 = FeedV1.getMsgHash(msg3)
-  t.deepEquals(msg3.metadata.prev, [msgHash2B], 'msg3.prev is msg2B')
+  t.deepEquals(
+    msg3.metadata.tangles[rootHash].prev,
+    [rootHash, msgHash2B],
+    'msg3.prev is root(lipmaa),msg2B(previous)'
+  )
   existing.set(msgHash3, msg3)
 
   const msgHash2A = FeedV1.getMsgHash(msg2A)
@@ -138,13 +190,15 @@ tape('create() handles DAG tips correctly', (t) => {
     keys,
     content: { text: '4' },
     type: 'post',
-    existing,
+    tangles: {
+      [rootHash]: existing,
+    },
     when: when + 4,
   })
   t.deepEquals(
-    msg4.metadata.prev,
-    [msgHash1, msgHash3, msgHash2A],
-    'msg4.prev is [msg1(lipmaa),msg3(previous),msg2A(old fork as tip)]'
+    msg4.metadata.tangles[rootHash].prev,
+    [msgHash3, msgHash2A],
+    'msg4.prev is [msg3(previous),msg2A(old fork as tip)]'
   )
 
   t.end()
diff --git a/test/feed-v1-invalid-prev.test.js b/test/feed-v1-invalid-prev.test.js
index 8ab9b08..7edeaa5 100644
--- a/test/feed-v1-invalid-prev.test.js
+++ b/test/feed-v1-invalid-prev.test.js
@@ -3,84 +3,67 @@ const base58 = require('bs58')
 const FeedV1 = require('../lib/feed-v1')
 const { generateKeypair } = require('./util')
 
-tape('invalid 1st msg with non-array prev', (t) => {
+tape('invalid msg with non-array prev', (t) => {
   const keys = generateKeypair('alice')
 
+  const rootMsg = FeedV1.createRoot(keys, 'post')
+  const rootHash = FeedV1.getMsgHash(rootMsg)
+
+  const existing = new Map([[rootHash, rootMsg]])
+
   const msg = FeedV1.create({
     keys,
     content: { text: 'Hello world!' },
     type: 'post',
-    existing: new Map(),
+    tangles: {
+      [rootHash]: existing,
+    },
     when: 1652030001000,
   })
-  msg.metadata.prev = null
+  msg.metadata.tangles[rootHash].prev = null
+  const msgHash = FeedV1.getMsgHash(msg)
 
-  FeedV1.validate(msg, new Map(), (err) => {
+  FeedV1.validate(msg, existing, msgHash, rootHash, (err) => {
     t.ok(err, 'invalid 2nd msg throws')
     t.match(err.message, /prev must be an array/, 'invalid 2nd msg description')
     t.end()
   })
 })
 
-tape('invalid msg with non-array prev', (t) => {
-  const keys = generateKeypair('alice')
-
-  const msg1 = FeedV1.create({
-    keys,
-    content: { text: 'Hello world!' },
-    type: 'post',
-    existing: new Map(),
-    when: 1652030001000,
-  })
-  const msgHash1 = FeedV1.getMsgHash(msg1)
-
-  const msg2 = FeedV1.create({
-    keys,
-    content: { text: 'Hello world!' },
-    type: 'post',
-    existing: new Map(),
-    when: 1652030002000,
-  })
-  msg2.metadata.prev = null
-
-  const existing = new Map()
-  existing.set(msgHash1, msg1)
-  FeedV1.validate(msg2, existing, (err) => {
-    t.ok(err, 'invalid 2nd msg throws')
-    t.match(
-      err.message,
-      /prev must be an array/,
-      'invalid 2nd msg description'
-    )
-    t.end()
-  })
-})
-
 tape('invalid msg with bad prev', (t) => {
   const keys = generateKeypair('alice')
 
+  const rootMsg = FeedV1.createRoot(keys, 'post')
+  const rootHash = FeedV1.getMsgHash(rootMsg)
+
+  const existing = new Map([[rootHash, rootMsg]])
+
   const msg1 = FeedV1.create({
     keys,
     content: { text: 'Hello world!' },
     type: 'post',
-    existing: new Map(),
+    tangles: {
+      [rootHash]: existing,
+    },
     when: 1652030001000,
   })
   const msgHash1 = FeedV1.getMsgHash(msg1)
+  existing.set(msgHash1, msg1)
 
   const msg2 = FeedV1.create({
     keys,
     content: { text: 'Hello world!' },
     type: 'post',
-    existing: new Map(),
+    tangles: {
+      [rootHash]: existing,
+    },
     when: 1652030002000,
   })
-  msg2.metadata.depth = 1
-  msg2.metadata.prev = [1234]
+  msg2.metadata.tangles[rootHash].depth = 1
+  msg2.metadata.tangles[rootHash].prev = [1234]
+  const msgHash2 = FeedV1.getMsgHash(msg2)
 
-  const existing = new Map()
-  existing.set(msgHash1, msg1)
-  FeedV1.validate(msg2, existing, (err) => {
+  FeedV1.validate(msg2, existing, msgHash2, rootHash, (err) => {
     t.ok(err, 'invalid 2nd msg throws')
     t.match(
       err.message,
@@ -94,30 +77,39 @@ tape('invalid msg with bad prev', (t) => {
 tape('invalid msg with URI in prev', (t) => {
   const keys = generateKeypair('alice')
 
+  const rootMsg = FeedV1.createRoot(keys, 'post')
+  const rootHash = FeedV1.getMsgHash(rootMsg)
+
+  const existing = new Map([[rootHash, rootMsg]])
+
   const msg1 = FeedV1.create({
     keys,
     content: { text: 'Hello world!' },
     type: 'post',
-    existing: new Map(),
+    tangles: {
+      [rootHash]: existing,
+    },
     when: 1652030001000,
   })
   const msgHash1 = FeedV1.getMsgHash(msg1)
+  existing.set(msgHash1, msg1)
 
   const msg2 = FeedV1.create({
     keys,
     content: { text: 'Hello world!' },
     type: 'post',
-    existing: new Map(),
+    tangles: {
+      [rootHash]: existing,
+    },
     when: 1652030002000,
   })
+  const msgHash2 = FeedV1.getMsgHash(msg2)
   const randBuf = Buffer.alloc(16).fill(16)
   const fakeMsgKey1 = `ppppp:message/v1/${base58.encode(randBuf)}`
-  msg2.metadata.depth = 1
-  msg2.metadata.prev = [fakeMsgKey1]
+  msg2.metadata.tangles[rootHash].depth = 1
+  msg2.metadata.tangles[rootHash].prev = [fakeMsgKey1]
 
-  const existing = new Map()
-  existing.set(msgHash1, msg1)
-  FeedV1.validate(msg2, existing, (err) => {
+  FeedV1.validate(msg2, existing, msgHash2, rootHash, (err) => {
     t.ok(err, 'invalid 2nd msg throws')
     t.match(
       err.message,
@@ -131,20 +123,30 @@ tape('invalid msg with URI in prev', (t) => {
 tape('invalid msg with unknown prev', (t) => {
   const keys = generateKeypair('alice')
 
+  const rootMsg = FeedV1.createRoot(keys, 'post')
+  const rootHash = FeedV1.getMsgHash(rootMsg)
+
+  const existing = new Map([[rootHash, rootMsg]])
+
   const msg1 = FeedV1.create({
     keys,
     content: { text: 'Hello world!' },
     type: 'post',
-    existing: new Map(),
+    tangles: {
+      [rootHash]: existing,
+    },
     when: 1652030001000,
   })
   const msgHash1 = FeedV1.getMsgHash(msg1)
+  existing.set(msgHash1, msg1)
 
   const unknownMsg = FeedV1.create({
     keys,
     content: { text: 'Alien' },
     type: 'post',
-    existing: new Map(),
+    tangles: {
+      [rootHash]: existing,
+    },
     when: 1652030001000,
   })
   const unknownMsgHash = FeedV1.getMsgHash(unknownMsg)
@@ -153,13 +155,14 @@ tape('invalid msg with unknown prev', (t) => {
     keys,
     content: { text: 'Hello world!' },
     type: 'post',
-    existing: new Map([[unknownMsgHash, unknownMsg]]),
+    tangles: {
+      [rootHash]: new Map([[rootHash, rootMsg], [unknownMsgHash, unknownMsg]]),
+    },
     when: 1652030002000,
   })
+  const msgHash2 = FeedV1.getMsgHash(msg2)
 
-  const existing = new Map()
-  existing.set(msgHash1, msg1)
-  FeedV1.validate(msg2, existing, (err) => {
+  FeedV1.validate(msg2, existing, msgHash2, rootHash, (err) => {
     t.ok(err, 'invalid 2nd msg throws')
     t.match(
       err.message,
diff --git a/test/feed-v1-invalid-type.test.js b/test/feed-v1-invalid-type.test.js
index f366fbf..0462cc1 100644
--- a/test/feed-v1-invalid-type.test.js
+++ b/test/feed-v1-invalid-type.test.js
@@ -12,7 +12,6 @@ tape('invalid type not a string', (t) => {
         content: { text: 'Hello world!' },
         when: 1652037377204,
         type: 123,
-        existing: new Map(),
       })
     },
     /type is not a string/,
@@ -31,7 +30,6 @@ tape('invalid type with "/" character', (t) => {
         content: { text: 'Hello world!' },
         when: 1652037377204,
         type: 'group/init',
-        existing: new Map(),
       })
     },
     /invalid type/,
@@ -50,7 +48,6 @@ tape('invalid type with "*" character', (t) => {
         content: { text: 'Hello world!' },
         when: 1652037377204,
         type: 'star*',
-        existing: new Map(),
       })
     },
     /invalid type/,
@@ -69,7 +66,6 @@ tape('invalid type too short', (t) => {
         content: { text: 'Hello world!' },
         when: 1652037377204,
         type: 'xy',
-        existing: new Map(),
       })
     },
     /shorter than 3/,
@@ -88,7 +84,6 @@ tape('invalid type too long', (t) => {
         content: { text: 'Hello world!' },
         when: 1652037377204,
         type: 'a'.repeat(120),
-        existing: new Map(),
       })
     },
     /100\+ characters long/,
diff --git a/test/feed-v1-lipmaa.test.js b/test/feed-v1-lipmaa.test.js
index f5d3bb4..2e7c01c 100644
--- a/test/feed-v1-lipmaa.test.js
+++ b/test/feed-v1-lipmaa.test.js
@@ -8,64 +8,132 @@ tape('lipmaa prevs', (t) => {
   const when = 1652037377204
   const existing = new Map()
 
+  const rootMsg = FeedV1.createRoot(keys, 'post')
+  const rootHash = FeedV1.getMsgHash(rootMsg)
+  existing.set(rootHash, rootMsg)
+
   const msg1 = FeedV1.create({
     keys,
     content,
     type: 'post',
-    existing: new Map(),
+    tangles: {
+      [rootHash]: existing,
+    },
     when: when + 1,
   })
   const msgHash1 = FeedV1.getMsgHash(msg1)
   existing.set(msgHash1, msg1)
-  t.deepEquals(msg1.metadata.prev, [], 'msg1.prev is empty')
+  t.equals(msg1.metadata.tangles[rootHash].depth, 1, 'msg1 depth')
+  t.deepEquals(msg1.metadata.tangles[rootHash].prev, [rootHash], 'msg1 prev')
 
   const msg2 = FeedV1.create({
     keys,
     content,
     type: 'post',
-    existing,
+    tangles: {
+      [rootHash]: existing,
+    },
     when: when + 2,
   })
   const msgHash2 = FeedV1.getMsgHash(msg2)
   existing.set(msgHash2, msg2)
-  t.deepEquals(msg2.metadata.prev, [msgHash1], 'msg2.prev is msg1')
+  t.equals(msg2.metadata.tangles[rootHash].depth, 2, 'msg2 depth')
+  t.deepEquals(
+    msg2.metadata.tangles[rootHash].prev,
+    [msgHash1],
+    'msg2 prev'
+  )
 
   const msg3 = FeedV1.create({
     keys,
     content,
     type: 'post',
-    existing,
+    tangles: {
+      [rootHash]: existing,
+    },
     when: when + 3,
   })
   const msgHash3 = FeedV1.getMsgHash(msg3)
   existing.set(msgHash3, msg3)
-  t.deepEquals(msg3.metadata.prev, [msgHash2], 'msg3.prev is msg2')
+  t.equals(msg3.metadata.tangles[rootHash].depth, 3, 'msg3 depth')
+  t.deepEquals(
+    msg3.metadata.tangles[rootHash].prev,
+    [rootHash, msgHash2],
+    'msg3 prev (has lipmaa!)'
+  )
 
   const msg4 = FeedV1.create({
     keys,
     content,
     type: 'post',
-    existing,
+    tangles: {
+      [rootHash]: existing,
+    },
     when: when + 4,
   })
   const msgHash4 = FeedV1.getMsgHash(msg4)
   existing.set(msgHash4, msg4)
+  t.equals(msg4.metadata.tangles[rootHash].depth, 4, 'msg4 depth')
   t.deepEquals(
-    msg4.metadata.prev,
-    [msgHash1, msgHash3],
-    'msg4.prev is msg1 and msg3'
+    msg4.metadata.tangles[rootHash].prev,
+    [msgHash3],
+    'msg4 prev'
   )
 
   const msg5 = FeedV1.create({
     keys,
     content,
     type: 'post',
-    existing,
+    tangles: {
+      [rootHash]: existing,
+    },
     when: when + 5,
   })
   const msgHash5 = FeedV1.getMsgHash(msg5)
   existing.set(msgHash5, msg5)
-  t.deepEquals(msg5.metadata.prev, [msgHash4], 'msg5.prev is msg4')
+  t.equals(msg5.metadata.tangles[rootHash].depth, 5, 'msg5 depth')
+  t.deepEquals(
+    msg5.metadata.tangles[rootHash].prev,
+    [msgHash4],
+    'msg5 prev'
+  )
+
+  const msg6 = FeedV1.create({
+    keys,
+    content,
+    type: 'post',
+    tangles: {
+      [rootHash]: existing,
+    },
+    when: when + 6,
+  })
+  const msgHash6 = FeedV1.getMsgHash(msg6)
+  existing.set(msgHash6, msg6)
+  t.equals(msg6.metadata.tangles[rootHash].depth, 6, 'msg6 depth')
+  t.deepEquals(
+    msg6.metadata.tangles[rootHash].prev,
+    [msgHash5],
+    'msg6 prev'
+  )
+
+  const msg7 = FeedV1.create({
+    keys,
+    content,
+    type: 'post',
+    tangles: {
+      [rootHash]: existing,
+    },
+    when: when + 7,
+  })
+  const msgHash7 = FeedV1.getMsgHash(msg7)
+  existing.set(msgHash7, msg7)
+  t.equals(msg7.metadata.tangles[rootHash].depth, 7, 'msg7 depth')
+  t.deepEquals(
+    msg7.metadata.tangles[rootHash].prev,
+    [msgHash3, msgHash6],
+    'msg7 prev (has lipmaa!)'
+  )
+
 
   t.end()
 })
diff --git a/test/feed-v1-tangles.test.js b/test/feed-v1-tangles.test.js
index da39951..66b6d5a 100644
--- a/test/feed-v1-tangles.test.js
+++ b/test/feed-v1-tangles.test.js
@@ -5,16 +5,32 @@ const { generateKeypair } = require('./util')
 tape('simple multi-author tangle', (t) => {
   const keysA = generateKeypair('alice')
   const keysB = generateKeypair('bob')
+  const existingA = new Map()
+  const existingB = new Map()
+
+  const rootMsgA = FeedV1.createRoot(keysA, 'post')
+  const rootHashA = FeedV1.getMsgHash(rootMsgA)
+  existingA.set(rootHashA, rootMsgA)
+
+  const rootMsgB = FeedV1.createRoot(keysB, 'post')
+  const rootHashB = FeedV1.getMsgHash(rootMsgB)
+  existingB.set(rootHashB, rootMsgB)
 
   const msg1 = FeedV1.create({
     keys: keysA,
     content: { text: 'Hello world!' },
     type: 'post',
-    existing: new Map(),
+    tangles: {
+      [rootHashA]: existingA,
+    },
     when: 1652030001000,
   })
   const msgHash1 = FeedV1.getMsgHash(msg1)
-  t.notOk(msg1.metadata.tangles, 'msg1 has no extra tangles')
+  t.deepEquals(
+    Object.keys(msg1.metadata.tangles),
+    [rootHashA],
+    'msg1 has only feed tangle'
+  )
 
   const msg2 = FeedV1.create({
     keys: keysB,
@@ -22,12 +38,24 @@ tape('simple multi-author tangle', (t) => {
     type: 'post',
     existing: new Map(),
     tangles: {
+      [rootHashB]: existingB,
       [msgHash1]: new Map([[msgHash1, msg1]]),
     },
     when: 1652030002000,
   })
-  t.ok(msg2.metadata.tangles, 'msg2 has extra tangles')
-  t.ok(msg2.metadata.tangles[msgHash1], 'msg2 has tangle for msgHash1')
+
+  t.deepEquals(
+    Object.keys(msg2.metadata.tangles),
+    [rootHashB, msgHash1],
+    'msg2 has feed tangle and misc tangle'
+  )
+  t.equal(msg2.metadata.tangles[rootHashB].depth, 1, 'msg2 feed tangle depth')
+  t.deepEquals(
+    msg2.metadata.tangles[rootHashB].prev,
+    [rootHashB],
+    'msg2 feed tangle prev'
+  )
+
   t.equal(msg2.metadata.tangles[msgHash1].depth, 1, 'msg2 has tangle depth 1')
   t.deepEquals(
     msg2.metadata.tangles[msgHash1].prev,
@@ -48,18 +76,29 @@ tape('lipmaa in multi-author tangle', (t) => {
   const existingB = new Map()
   const tangleExisting = new Map()
 
+  const rootMsgA = FeedV1.createRoot(keysA, 'post')
+  const rootHashA = FeedV1.getMsgHash(rootMsgA)
+  existingA.set(rootHashA, rootMsgA)
+
+  const rootMsgB = FeedV1.createRoot(keysB, 'post')
+  const rootHashB = FeedV1.getMsgHash(rootMsgB)
+  existingB.set(rootHashB, rootMsgB)
+
+
   const msg1 = FeedV1.create({
     keys: keysA,
     content,
     type: 'post',
-    existing: existingA,
+    tangles: {
+      [rootHashA]: existingA,
+    },
     when: when + 1,
   })
   const msgHash1 = FeedV1.getMsgHash(msg1)
   existingA.set(msgHash1, msg1)
   tangleExisting.set(msgHash1, msg1)
 
-  t.notOk(msg1.metadata.tangles, 'A:msg1 has no extra tangles')
+  t.deepEquals(Object.keys(msg1.metadata.tangles),[rootHashA], 'A:msg1 has only feed tangle')
 
   const msg2 = FeedV1.create({
     keys: keysB,
@@ -67,6 +106,7 @@ tape('lipmaa in multi-author tangle', (t) => {
     type: 'post',
     existing: existingB,
     tangles: {
+      [rootHashB]: existingB,
       [msgHash1]: tangleExisting,
     },
     when: when + 2,
@@ -87,6 +127,7 @@ tape('lipmaa in multi-author tangle', (t) => {
     type: 'post',
     existing: existingB,
     tangles: {
+      [rootHashB]: existingB,
       [msgHash1]: tangleExisting,
     },
     when: when + 3,
@@ -107,6 +148,7 @@ tape('lipmaa in multi-author tangle', (t) => {
     type: 'post',
     existing: existingA,
     tangles: {
+      [rootHashA]: existingA,
       [msgHash1]: tangleExisting,
     },
     when: when + 4,
diff --git a/test/feed-v1-validate.test.js b/test/feed-v1-validate.test.js
index ff36551..07d4358 100644
--- a/test/feed-v1-validate.test.js
+++ b/test/feed-v1-validate.test.js
@@ -3,106 +3,42 @@ const base58 = require('bs58')
 const FeedV1 = require('../lib/feed-v1')
 const { generateKeypair } = require('./util')
 
-tape('validate 1st msg', (t) => {
+tape('validate root msg', (t) => {
   const keys = generateKeypair('alice')
+  const existing = new Map()
 
-  const msg = FeedV1.create({
-    keys,
-    content: { text: 'Hello world!' },
-    type: 'post',
-    existing: new Map(),
-    when: 1652030001000,
-  })
+  const rootMsg = FeedV1.createRoot(keys, 'post')
+  const rootHash = FeedV1.getMsgHash(rootMsg)
+  existing.set(rootHash, rootMsg)
 
-  FeedV1.validate(msg, [], (err) => {
+  FeedV1.validate(rootMsg, existing, rootHash, rootHash, (err) => {
     if (err) console.log(err)
-    t.error(err, 'valid 1st msg')
+    t.error(err, 'valid root msg')
     t.end()
   })
 })
 
-tape('validate 2nd msg with existing nativeMsg', (t) => {
+tape('validate 2nd msg with existing root', (t) => {
   const keys = generateKeypair('alice')
+  const existing = new Map()
+
+  const rootMsg = FeedV1.createRoot(keys, 'post')
+  const rootHash = FeedV1.getMsgHash(rootMsg)
+  existing.set(rootHash, rootMsg)
 
   const msg1 = FeedV1.create({
     keys,
     content: { text: 'Hello world!' },
     type: 'post',
-    existing: new Map(),
+    tangles: {
+      [rootHash]: existing,
+    },
     when: 1652030001000,
   })
   const msgHash1 = FeedV1.getMsgHash(msg1)
-
-  const msg2 = FeedV1.create({
-    keys,
-    content: { text: 'Hello world!' },
-    type: 'post',
-    existing: new Map([[msgHash1, msg1]]),
-    when: 1652030002000,
-  })
-
-  const existing = new Map()
   existing.set(msgHash1, msg1)
-  FeedV1.validate(msg2, existing, (err) => {
-    if (err) console.log(err)
-    t.error(err, 'valid 2nd msg')
-    t.end()
-  })
-})
 
-tape('validate 2nd msg with existing msgId', (t) => {
-  const keys = generateKeypair('alice')
-
-  const msg1 = FeedV1.create({
-    keys,
-    content: { text: 'Hello world!' },
-    type: 'post',
-    prev: [],
-    existing: new Map(),
-    when: 1652030001000,
-  })
-  const msgHash1 = FeedV1.getMsgHash(msg1)
-
-  const msg2 = FeedV1.create({
-    keys,
-    content: { text: 'Hello world!' },
-    type: 'post',
-    existing: new Map([[msgHash1, msg1]]),
-    when: 1652030002000,
-  })
-
-  const existing = new Map()
-  existing.set(msgHash1, msg1)
-  FeedV1.validate(msg2, existing, (err) => {
-    if (err) console.log(err)
-    t.error(err, 'valid 2nd msg')
-    t.end()
-  })
-})
-
-tape('validate 2nd msg with existing KVT', (t) => {
-  const keys = generateKeypair('alice')
-
-  const msg1 = FeedV1.create({
-    keys,
-    content: { text: 'Hello world!' },
-    type: 'post',
-    existing: new Map(),
-    when: 1652030001000,
-  })
-  const msgHash1 = FeedV1.getMsgHash(msg1)
-
-  const msg2 = FeedV1.create({
-    keys,
-    content: { text: 'Hello world!' },
-    type: 'post',
-    existing: new Map([[msgHash1, msg1]]),
-    when: 1652030002000,
-  })
-
-  const existing = new Map()
-  existing.set(msgHash1, msg1)
-  FeedV1.validate(msg2, existing, (err) => {
+  FeedV1.validate(msg1, existing, msgHash1, rootHash, (err) => {
     if (err) console.log(err)
     t.error(err, 'valid 2nd msg')
     t.end()
@@ -112,36 +48,38 @@ tape('validate 2nd msg with existing KVT', (t) => {
 tape('validate 2nd forked msg', (t) => {
   const keys = generateKeypair('alice')
 
-  const msg1 = FeedV1.create({
+  const existing = new Map()
+
+  const rootMsg = FeedV1.createRoot(keys, 'post')
+  const rootHash = FeedV1.getMsgHash(rootMsg)
+  existing.set(rootHash, rootMsg)
+
+  const msg1A = FeedV1.create({
     keys,
     content: { text: 'Hello world!' },
     type: 'post',
+    tangles: {
+      [rootHash]: existing,
+    },
     existing: new Map(),
     when: 1652030001000,
   })
-  const msgHash1 = FeedV1.getMsgHash(msg1)
+  const msgHash1A = FeedV1.getMsgHash(msg1A)
 
-  const msg2A = FeedV1.create({
+  const msg1B = FeedV1.create({
     keys,
     content: { text: 'Hello world!' },
     type: 'post',
-    existing: new Map([[msgHash1, msg1]]),
+    tangles: {
+      [rootHash]: existing,
+    },
     when: 1652030002000,
   })
-  const msgHash2A = FeedV1.getMsgHash(msg2A)
+  const msgHash1B = FeedV1.getMsgHash(msg1B)
 
-  const msg2B = FeedV1.create({
-    keys,
-    content: { text: 'Hello world!' },
-    type: 'post',
-    existing: new Map([[msgHash1, msg1]]),
-    when: 1652030003000,
-  })
-
-  const existing = new Map()
-  existing.set(msgHash1, msg1)
-  existing.set(msgHash2A, msg2A)
-  FeedV1.validate(msg2B, existing, (err) => {
+  existing.set(msgHash1A, msg1A)
+  existing.set(msgHash1B, msg1B)
+  FeedV1.validate(msg1B, existing, msgHash1B, rootHash, (err) => {
     if (err) console.log(err)
     t.error(err, 'valid 2nd forked msg')
     t.end()
@@ -151,29 +89,28 @@ tape('validate 2nd forked msg', (t) => {
 tape('invalid msg with unknown previous', (t) => {
   const keys = generateKeypair('alice')
 
+  const existing = new Map()
+
+  const rootMsg = FeedV1.createRoot(keys, 'post')
+  const rootHash = FeedV1.getMsgHash(rootMsg)
+  existing.set(rootHash, rootMsg)
+
   const msg1 = FeedV1.create({
     keys,
     content: { text: 'Hello world!' },
     type: 'post',
-    existing: new Map(),
+    tangles: {
+      [rootHash]: existing,
+    },
     when: 1652030001000,
   })
   const msgHash1 = FeedV1.getMsgHash(msg1)
 
-  const fakeMsgKey1 = base58.encode(Buffer.alloc(16).fill(42))
+  const fakeMsgHash = base58.encode(Buffer.alloc(16).fill(42))
 
-  const msg2 = FeedV1.create({
-    keys,
-    content: { text: 'Hello world!' },
-    type: 'post',
-    existing: new Map([[msgHash1, msg1]]),
-    when: 1652030002000,
-  })
-  msg2.metadata.prev = [fakeMsgKey1]
+  msg1.metadata.tangles[rootHash].prev = [fakeMsgHash]
 
-  const existing = new Map()
-  existing.set(msgHash1, msg1)
-  FeedV1.validate(msg2, existing, (err) => {
+  FeedV1.validate(msg1, existing, msgHash1, rootHash, (err) => {
     t.ok(err, 'invalid 2nd msg throws')
     t.match(
       err.message,
diff --git a/test/msgs-iterator.test.js b/test/msgs-iterator.test.js
index 5cd75c5..18f4c70 100644
--- a/test/msgs-iterator.test.js
+++ b/test/msgs-iterator.test.js
@@ -31,6 +31,7 @@ test('msgs() iterator', async (t) => {
   const posts = []
   const abouts = []
   for (const msg of peer.db.msgs()) {
+    if (!msg.content) continue
     if (msg.metadata.type === 'post') posts.push(msg.content.text)
     else if (msg.metadata.type === 'about') abouts.push(msg.content.name)
   }
diff --git a/test/on-record-added.test.js b/test/on-record-added.test.js
index 550ec84..2dd3e7d 100644
--- a/test/on-record-added.test.js
+++ b/test/on-record-added.test.js
@@ -31,8 +31,10 @@ test('onRecordAdded', async (t) => {
 
   await p(setTimeout)(500)
 
-  t.equal(listened.length, 1)
-  t.deepEquals(listened, [rec1])
+  t.equal(listened.length, 2)
+  t.deepEquals(listened[0].msg.content, null, 'root')
+  t.deepEquals(listened[0].msg.metadata.when, 0, 'root')
+  t.deepEquals(listened[1], rec1, 'actual record')
 
   remove()
   await p(peer.close)(true)
diff --git a/test/re-open.test.js b/test/re-open.test.js
index b6b2698..f2d87eb 100644
--- a/test/re-open.test.js
+++ b/test/re-open.test.js
@@ -46,6 +46,7 @@ test('create some msgs, close, re-open', async (t) => {
 
   const texts = []
   for (const msg of peer2.db.msgs()) {
+    if (!msg.content) continue
     texts.push(msg.content.text)
   }
 
diff --git a/test/records-iterator.test.js b/test/records-iterator.test.js
index e2ac87f..1dd712c 100644
--- a/test/records-iterator.test.js
+++ b/test/records-iterator.test.js
@@ -30,6 +30,7 @@ test('records() iterator', async (t) => {
 
   let count = 0
   for (const rec of peer.db.records()) {
+    if (!rec.msg.content) continue
     t.true(rec.misc.size > rec.msg.metadata.size)
     count++
   }