diff --git a/matrix/rooms.py b/matrix/rooms.py
index 15d901e..b075210 100644
--- a/matrix/rooms.py
+++ b/matrix/rooms.py
@@ -221,8 +221,9 @@ class RoomInfo():
 
             try:
                 message = RoomMembershipMessage(
-                    event.event_id, event.sender, event.age,
+                    event.event_id, event.sender, event.timestamp,
                     "has joined", "join")
+
                 return event, message
             except AttributeError:
                 return event, None