Quote Originally Posted by Stuperman
The AI should use trusted ally to expand in the other direction, go against a common enemy or attck the largest threat to themselves. They should NOT sit around till your empire is the biggest threat, then give up years of peace cause the player triggered it.
As far as I can tell, this is the case. I had 3 specific alliances (more, but just these 3 are relevant) on my northern Byz front to stabilize it at the beginning of my current game. I ended up having to break with Poland because Hungary attacked about 20 turns in, and the Venitians backstabbed me about 40 turns in and attacked me. So far my alliance with Hungary is holding, but I think they'd drop it/backstab me in a heartbeat if they didn't already have their hands full. As of late, I've seen a few small stacks probing my borders, and I noticed that they've also overrun most of the territories north of me. I haven't seen or paid attention to elsewhere on the map, but it would appear that this statement by Stuperman is basically correct.