diff --git a/specs/capella/fork.md b/specs/capella/fork.md
index e2493d33b..49bf8744f 100644
--- a/specs/capella/fork.md
+++ b/specs/capella/fork.md
@@ -129,8 +129,10 @@ def upgrade_to_capella(pre: bellatrix.BeaconState) -> BeaconState:
         # Execution-layer
         latest_execution_payload_header=latest_execution_payload_header,
         # Withdrawals
-        next_withdrawal_index=WithdrawalIndex(0),
-        next_withdrawal_validator_index=ValidatorIndex(0),
+        next_withdrawal_index=WithdrawalIndex(0),  # [New in Capella]
+        next_withdrawal_validator_index=ValidatorIndex(0),  # [New in Capella]
+        # Deep history valid from Capella onwards
+        historical_summaries=List[HistoricalSummary, HISTORICAL_ROOTS_LIMIT]([]),  # [New in Capella]
     )
 
     return post
diff --git a/specs/eip4844/fork.md b/specs/eip4844/fork.md
index 60a53f91f..39521879a 100644
--- a/specs/eip4844/fork.md
+++ b/specs/eip4844/fork.md
@@ -131,6 +131,8 @@ def upgrade_to_eip4844(pre: capella.BeaconState) -> BeaconState:
         # Withdrawals
         next_withdrawal_index=pre.next_withdrawal_index,
         next_withdrawal_validator_index=pre.next_withdrawal_validator_index,
+        # Deep history valid from Capella onwards
+        historical_summaries=pre.historical_summaries,
     )
 
     return post