I've often noticed, when having a defensive pact with another civ, that when someone declares war on me and my ally automatically declares war on them, my ally doesn't actually do anything during the war to assist me. In my latest game (as England), I had a defensive pact with Cyrus so when Alexander declared war, Cyrus declared on him. However, not once did I see Cyrus do anything remotely related to helping me out in terms of military (even though he was the most powerful civ on the planet). It was also late game, so everyone had access to moving troops around by various means (land, sea, air, etc). Is this normal for the AI or does it depend on map type or relations with other civs?