Monty is actually the most predictable of the aggressive bunch. He will ALWAYS attack you if he gets the chance. If you're too weak, or if you're in a war with someone else and haven't left your territory properly defended. He's basically an indicator of how well you've planned your military strategy.
You have two choices: take him out first, or make him your pet. The first is obvious. The second one requires you to be very powerful too - check the Power Graph for info - and provide him with better targets. Bribe him to get in wars with his neighbours. That won't spare you though, so be careful.
Of course, you can become the backstabber too...
Other well-known maniacs:
- Alexander, crazy backstabber, can't wait for you to get in a war with someone else
- Isabella: either you're with her (same religion) or you're in for a war
- Cathy: I had her twice as neighbour and she attacked me both times, once while we were in a common war against another AI.
Napoleon, the Khans, and I think the Caesars too are bound to attack you from time to time. Julius can be pleased though if you share the same religion even if you're low on power. I've done it in the "Lust for Gold" challenge and managed to stop any war before it happened. I've also been attacked in another game by Praetorians so don't get him mad.
There are probably others that I've missed. You'll find out eventually.
