diff --git a/core/common/span_adl.hpp b/core/common/span_adl.hpp
index 7fd8b494d0..cd09a9bb73 100644
--- a/core/common/span_adl.hpp
+++ b/core/common/span_adl.hpp
@@ -40,8 +40,9 @@ auto operator<=>(const SpanAdl<T> &l_, const auto &r_)
 }
 
 template <typename T>
-bool operator==(const SpanAdl<T> &l_, const auto &r)
-  requires(requires { std::span<const T>{r}; })
+bool operator==(const SpanAdl<T> &l_, const auto &r_)
+  requires(requires { std::span<const T>{r_}; })
 {
-  return (l_ <=> r) == 0;
+  std::span r{r_};
+  return l_.v.size() == r.size() and (l_ <=> r) == 0;
 }
diff --git a/core/consensus/grandpa/environment.hpp b/core/consensus/grandpa/environment.hpp
index a366238000..fed719ef55 100644
--- a/core/consensus/grandpa/environment.hpp
+++ b/core/consensus/grandpa/environment.hpp
@@ -126,6 +126,9 @@ namespace kagome::consensus::grandpa {
     /// authority set changes.
     virtual outcome::result<void> reportEquivocation(
         const VotingRound &round, const Equivocation &equivocation) const = 0;
+
+    virtual outcome::result<void> makeAncestry(
+        GrandpaJustification &justification) const = 0;
   };
 
 }  // namespace kagome::consensus::grandpa
diff --git a/core/consensus/grandpa/impl/environment_impl.cpp b/core/consensus/grandpa/impl/environment_impl.cpp
index 6379e8a289..0d61202877 100644
--- a/core/consensus/grandpa/impl/environment_impl.cpp
+++ b/core/consensus/grandpa/impl/environment_impl.cpp
@@ -20,6 +20,7 @@
 #include "consensus/grandpa/has_authority_set_change.hpp"
 #include "consensus/grandpa/i_verified_justification_queue.hpp"
 #include "consensus/grandpa/justification_observer.hpp"
+#include "consensus/grandpa/make_ancestry.hpp"
 #include "consensus/grandpa/movable_round_state.hpp"
 #include "consensus/grandpa/voting_round.hpp"
 #include "consensus/grandpa/voting_round_error.hpp"
@@ -504,4 +505,8 @@ namespace kagome::consensus::grandpa {
     return outcome::success();
   }
 
+  outcome::result<void> EnvironmentImpl::makeAncestry(
+      GrandpaJustification &justification) const {
+    return grandpa::makeAncestry(justification, *block_tree_);
+  }
 }  // namespace kagome::consensus::grandpa
diff --git a/core/consensus/grandpa/impl/environment_impl.hpp b/core/consensus/grandpa/impl/environment_impl.hpp
index 4a4bc161b2..940418b5b0 100644
--- a/core/consensus/grandpa/impl/environment_impl.hpp
+++ b/core/consensus/grandpa/impl/environment_impl.hpp
@@ -136,6 +136,9 @@ namespace kagome::consensus::grandpa {
         const VotingRound &round,
         const Equivocation &equivocation) const override;
 
+    outcome::result<void> makeAncestry(
+        GrandpaJustification &justification) const override;
+
    private:
     std::shared_ptr<blockchain::BlockTree> block_tree_;
     std::shared_ptr<blockchain::BlockHeaderRepository> header_repository_;
diff --git a/core/consensus/grandpa/impl/voting_round_impl.cpp b/core/consensus/grandpa/impl/voting_round_impl.cpp
index a349eee459..fe808fae71 100644
--- a/core/consensus/grandpa/impl/voting_round_impl.cpp
+++ b/core/consensus/grandpa/impl/voting_round_impl.cpp
@@ -653,7 +653,10 @@ namespace kagome::consensus::grandpa {
         .round_number = round_number_,
         .block_info = block,
         .items = getPrecommitJustification(block, precommits_->getMessages())};
-    // TODO(turuslan): #1931, make justification ancestry
+
+    if (auto r = env_->makeAncestry(justification); not r) {
+      SL_ERROR(logger_, "doCommit: makeAncestry: {}", r.error());
+    }
 
     SL_DEBUG(logger_,
              "Round #{}: Sending commit message for block {}",
diff --git a/core/consensus/grandpa/make_ancestry.hpp b/core/consensus/grandpa/make_ancestry.hpp
new file mode 100644
index 0000000000..4c009466fe
--- /dev/null
+++ b/core/consensus/grandpa/make_ancestry.hpp
@@ -0,0 +1,40 @@
+/**
+ * Copyright Quadrivium LLC
+ * All Rights Reserved
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#pragma once
+
+#include <unordered_set>
+
+#include "blockchain/block_tree.hpp"
+#include "consensus/grandpa/structs.hpp"
+#include "consensus/grandpa/voting_round_error.hpp"
+
+namespace kagome::consensus::grandpa {
+  /**
+   * Make ancestry merke proof for GrandpaJustification.
+   * https://github.com/paritytech/polkadot-sdk/blob/4842faf65d3628586d304fbcb6cb19b17b4a629c/substrate/client/consensus/grandpa/src/justification.rs#L64-L126
+   */
+  inline outcome::result<void> makeAncestry(
+      GrandpaJustification &justification,
+      const blockchain::BlockTree &block_tree) {
+    std::vector<primitives::BlockHeader> blocks;
+    std::unordered_set<primitives::BlockInfo> seen;
+    for (auto &m : justification.items) {
+      auto info = m.getBlockInfo();
+      while (info != justification.block_info and not seen.contains(info)) {
+        if (info.number <= justification.block_info.number) {
+          return VotingRoundError::CANT_MAKE_ANCESTRY;
+        }
+        OUTCOME_TRY(block, block_tree.getBlockHeader(info.hash));
+        seen.emplace(info);
+        info = *block.parentInfo();
+        blocks.emplace_back(std::move(block));
+      }
+    }
+    justification.votes_ancestries = blocks;
+    return outcome::success();
+  }
+}  // namespace kagome::consensus::grandpa
diff --git a/core/consensus/grandpa/voting_round_error.cpp b/core/consensus/grandpa/voting_round_error.cpp
index 966282fa65..51151f9db8 100644
--- a/core/consensus/grandpa/voting_round_error.cpp
+++ b/core/consensus/grandpa/voting_round_error.cpp
@@ -51,6 +51,8 @@ OUTCOME_CPP_DEFINE_CATEGORY(kagome::consensus::grandpa, VotingRoundError, e) {
       return "Can't get best prevote candidate";
     case E::ROUND_IS_NOT_FINALIZABLE:
       return "Round is not finalizable";
+    case E::CANT_MAKE_ANCESTRY:
+      return "Can't make ancestry";
   }
   return "Unknown error (invalid VotingRoundError)";
 }
diff --git a/core/consensus/grandpa/voting_round_error.hpp b/core/consensus/grandpa/voting_round_error.hpp
index 3d183917ab..d3270e3c65 100644
--- a/core/consensus/grandpa/voting_round_error.hpp
+++ b/core/consensus/grandpa/voting_round_error.hpp
@@ -29,7 +29,8 @@ namespace kagome::consensus::grandpa {
     EQUIVOCATED_VOTE,
     VOTE_OF_KNOWN_EQUIVOCATOR,
     NO_PREVOTE_CANDIDATE,
-    ROUND_IS_NOT_FINALIZABLE
+    ROUND_IS_NOT_FINALIZABLE,
+    CANT_MAKE_ANCESTRY,
   };
 
 }
diff --git a/test/mock/core/consensus/grandpa/environment_mock.hpp b/test/mock/core/consensus/grandpa/environment_mock.hpp
index 98a33eac02..b4c975e424 100644
--- a/test/mock/core/consensus/grandpa/environment_mock.hpp
+++ b/test/mock/core/consensus/grandpa/environment_mock.hpp
@@ -81,6 +81,11 @@ namespace kagome::consensus::grandpa {
                  std::vector<SignedPrecommit> precommit_justification,
                  BlockInfo best_final_candidate),
                 (override));
+
+    MOCK_METHOD(outcome::result<void>,
+                makeAncestry,
+                (GrandpaJustification &),
+                (const, override));
   };
 
 }  // namespace kagome::consensus::grandpa