diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 617452be6..2e3cbe2aa 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -400,7 +400,7 @@ class FederationHandler(BaseHandler):
             )
 
             try:
-                event_stream_id, max_stream_id = yield self._persist_auth_tree(
+                yield self._persist_auth_tree(
                     origin, auth_chain, state, event
                 )
             except AuthError as e: