diff --git a/proto/umbra/base.proto b/proto/umbra/base.proto
index 3c7e98d..61fdf35 100644
--- a/proto/umbra/base.proto
+++ b/proto/umbra/base.proto
@@ -35,7 +35,7 @@ message HistoryEntry {
       int32 lamport_timestamp = 10;    
       repeated HistoryEntry causal_history = 11;   
       bytes bloom_filter = 12; 
-      optional bytes content = 20;
+      bytes content = 20;
   }