diff --git a/fluffy/common/common_types.nim b/fluffy/common/common_types.nim
index 725b85f7a..da4d49acb 100644
--- a/fluffy/common/common_types.nim
+++ b/fluffy/common/common_types.nim
@@ -9,14 +9,15 @@
 
 import
   ssz_serialization/types,
-  stew/byteutils
+  stew/byteutils, nimcrypto/hash
 
 type
   ByteList* = List[byte, 2048]
   Bytes2* = array[2, byte]
   Bytes32* = array[32, byte]
 
-  ContentId* = Uint256
+  ContentId* = UInt256
+  BlockHash* = MDigest[32 * 8] # Bytes32
 
 func `$`*(x: ByteList): string =
   x.asSeq.toHex()
diff --git a/fluffy/network/header/header_content.nim b/fluffy/network/header/header_content.nim
new file mode 100644
index 000000000..06f4152f9
--- /dev/null
+++ b/fluffy/network/header/header_content.nim
@@ -0,0 +1,78 @@
+# Nimbus
+# Copyright (c) 2022 Status Research & Development GmbH
+# Licensed and distributed under either of
+#   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
+#   * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
+# at your option. This file may not be copied, modified, or distributed except according to those terms.
+
+# https://github.com/ethereum/portal-network-specs/blob/master/header-gossip-network.md
+
+{.push raises: [Defect].}
+
+import
+  nimcrypto/[sha2, hash],
+  ssz_serialization, ssz_serialization/merkleization,
+  eth/common/eth_types,
+  ../../common/common_types
+
+export merkleization
+
+const
+  epochSize = 8192 # blocks
+  maxHistoricalEpochs = 100_000 # Doesn't really need a limit, does it?
+
+type
+  # Header Gossip Content Keys
+  # https://github.com/ethereum/portal-network-specs/blob/master/header-gossip-network.md#content-keys
+
+  ContentType* = enum
+    accumulatorSnapshot = 0x00
+    newBlockHeader = 0x01
+
+  AccumulatorSnapshotKey* = object
+    accumulatorRootHash*: Bytes32
+
+  NewBlockHeaderKey* = object
+    blockHash*: BlockHash
+    blockNumber*: UInt256
+
+  ContentKey* = object
+    case contentType*: ContentType
+    of accumulatorSnapshot:
+      accumulatorSnapshotKey*: AccumulatorSnapshotKey
+    of newBlockHeader:
+      newBlockHeaderKey*: NewBlockHeaderKey
+
+  # Header Accumulator
+  # https://github.com/ethereum/portal-network-specs/blob/master/header-gossip-network.md#accumulator-snapshot
+
+  HeaderRecord = object
+    blockHash: BlockHash
+    totalDifficulty: UInt256
+
+  EpochAccumulator = List[HeaderRecord, epochSize]
+
+  Accumulator* = object
+    historicalEpochs*: List[Bytes32, maxHistoricalEpochs]
+    currentEpoch*: EpochAccumulator
+
+func updateAccumulator*(a: var Accumulator, header: BlockHeader) =
+  let lastTotalDifficulty =
+    if a.currentEpoch.len() == 0:
+      0.stuint(256)
+    else:
+      a.currentEpoch[^1].totalDifficulty
+
+  if a.currentEpoch.len() == epochSize:
+    let epochHash = hash_tree_root(a.currentEpoch)
+
+    doAssert(a.historicalEpochs.add(epochHash.data))
+    a.currentEpoch = EpochAccumulator.init(@[])
+
+  let headerRecord =
+    HeaderRecord(
+      blockHash: header.blockHash(),
+      totalDifficulty: lastTotalDifficulty + header.difficulty)
+
+  let res = a.currentEpoch.add(headerRecord)
+  doAssert(res, "Can't fail because of currentEpoch length check")
diff --git a/fluffy/network/history/history_content.nim b/fluffy/network/history/history_content.nim
index a99e6a14b..dd459f770 100644
--- a/fluffy/network/history/history_content.nim
+++ b/fluffy/network/history/history_content.nim
@@ -23,8 +23,6 @@ type
     blockBody = 0x01
     receipts = 0x02
 
-  BlockHash* = MDigest[32 * 8] # Bytes32
-
   ContentKeyType* = object
     chainId*: uint16
     blockHash*: BlockHash
diff --git a/fluffy/populate_db.nim b/fluffy/populate_db.nim
index aacb1f080..e17b31ee0 100644
--- a/fluffy/populate_db.nim
+++ b/fluffy/populate_db.nim
@@ -15,6 +15,8 @@ import
   ./network/wire/portal_protocol,
   ./network/history/history_content
 
+export results
+
 # Helper calls to, offline, populate the database with the current existing json
 # files with block data. Might move to some other storage format later on.
 # Perhaps https://github.com/status-im/nimbus-eth2/blob/stable/docs/e2store.md
@@ -137,6 +139,22 @@ iterator blocks*(
     else:
       error "Failed reading block from block data", error = res.error
 
+proc readBlockHeader*(blockData: BlockData): Result[BlockHeader, string] =
+  var rlp =
+    try:
+      rlpFromHex(blockData.rlp)
+    except ValueError as e:
+      return err("Invalid hex for rlp block data, number " &
+        $blockData.number & ": " & e.msg)
+
+  if rlp.enterList():
+    try:
+      return ok(rlp.read(BlockHeader))
+    except RlpError as e:
+      return err("Invalid header, number " & $blockData.number & ": " & e.msg)
+  else:
+    return err("Item is not a valid rlp list, number " & $blockData.number)
+
 # TODO pass nodeid as uint256 so it will be possible to use put method which
 # preserves size
 proc populateHistoryDb*(
@@ -146,7 +164,7 @@ proc populateHistoryDb*(
   for b in blocks(blockData, verify):
     for value in b:
       # Note: This is the slowest part due to the hashing that takes place.
-      # TODO use put method which preserves size 
+      # TODO use put method which preserves size
       db.put(history_content.toContentId(value[0]), value[1])
 
   ok()
diff --git a/fluffy/tests/all_fluffy_tests.nim b/fluffy/tests/all_fluffy_tests.nim
index 6a052dc57..f75799792 100644
--- a/fluffy/tests/all_fluffy_tests.nim
+++ b/fluffy/tests/all_fluffy_tests.nim
@@ -15,6 +15,7 @@ import
   ./test_state_network,
   ./test_history_content,
   ./test_history_validation,
+  ./test_header_content,
   ./test_content_db,
   ./test_discovery_rpc,
   ./test_bridge_parser
diff --git a/fluffy/tests/blocks/mainnet_blocks_1-2.json b/fluffy/tests/blocks/mainnet_blocks_1-2.json
new file mode 100644
index 000000000..3a25abc1e
--- /dev/null
+++ b/fluffy/tests/blocks/mainnet_blocks_1-2.json
@@ -0,0 +1,10 @@
+{
+  "0x88e96d4537bea4d9c05d12549907b32561d3bf31f45aae734cdc119f13406cb6": {
+    "rlp": "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",
+    "number": 1
+  },
+  "0xb495a1d7e6663152ae92708da4843337b958146015a2802f4193a410044698c9": {
+    "rlp": "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",
+    "number": 2
+  }
+}
diff --git a/fluffy/tests/test_header_content.nim b/fluffy/tests/test_header_content.nim
new file mode 100644
index 000000000..fbb8dc12b
--- /dev/null
+++ b/fluffy/tests/test_header_content.nim
@@ -0,0 +1,46 @@
+# Nimbus
+# Copyright (c) 2022 Status Research & Development GmbH
+# Licensed and distributed under either of
+#   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
+#   * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
+# at your option. This file may not be copied, modified, or distributed except according to those terms.
+
+{.used.}
+
+{.push raises: [Defect].}
+
+import
+  std/tables,
+  unittest2, stew/byteutils,
+  eth/common/eth_types,
+  ../network/header/header_content,
+  ../populate_db
+
+suite "Header Gossip Content":
+  test "Header Accumulator Update":
+    const dataFile = "./fluffy/tests/blocks/mainnet_blocks_1-2.json"
+    let blockDataRes = readBlockDataTable(dataFile)
+
+    check blockDataRes.isOk()
+    let blockData = blockDataRes.get()
+
+    var headers: seq[BlockHeader]
+    headers.setLen(blockData.len())
+
+    for k, v in blockData.pairs:
+      let res = v.readBlockHeader()
+      check res.isOk()
+      let header = res.get()
+      headers[header.blockNumber.truncate(int) - 1] = header
+
+    var accumulator: Accumulator
+
+    updateAccumulator(accumulator, headers[0])
+
+    check accumulator.hash_tree_root().data.toHex() ==
+      "411548579b5f6c651e6e1e56c3dc3fae6f389c663c0c910e462a4b806831fef6"
+
+    updateAccumulator(accumulator, headers[1])
+
+    check accumulator.hash_tree_root().data.toHex() ==
+      "e8dbd17538189d9a5b77001ff80c4ff6d841ceb0a3d374d17ddc4098550f5f93"
diff --git a/nimbus.nimble b/nimbus.nimble
index 147c5706e..69e6f0c74 100644
--- a/nimbus.nimble
+++ b/nimbus.nimble
@@ -80,4 +80,4 @@ task test_portal_testnet, "Build test_portal_testnet":
 task testfluffy, "Run fluffy tests":
   # Need the nimbus_db_backend in state network tests as we need a Hexary to
   # start from, even though it only uses the MemoryDb.
-  test "fluffy/tests", "all_fluffy_tests", "-d:chronicles_log_level=ERROR -d:chronosStrictException -d:nimbus_db_backend=sqlite"
+  test "fluffy/tests", "all_fluffy_tests", "-d:chronicles_log_level=ERROR -d:chronosStrictException -d:nimbus_db_backend=sqlite -d:PREFER_BLST_SHA256=false"