Playing last night on a small map, monarch level, I found myself with a slightly smallesh empire on the eastern end of the pangea. The Persians were on the western end, with the Iroquios and Egyptians between us. There were also several minor civs. Anyway, the Persians wiped out one of these minor civs and were getting really big. They threatened me, I told them to shove it and they declared war. I wasn't really worried, especially when I signed an alliance against them with the Iroquios and the Egytpians. I felt pretty safe. Suddenly, a stack of 10 uninjured cavalry appear on my border with Egypt. The Egyptians held a good bit of territory, and there was no way to go around them. So how did 10 cavalry come unscathed through their enemies land? I am guessing that the AI knows what the objective is of other AI units, so the Egytians, realizing these cavalry were not coming for them simply let them through. I fought off this stack, and then another, larger one appeared, and then another. All this time the Persians and egytians were at war with each other. I ended up getting crushed, and after losing 5 cites (half my empire) I just gave up. Has anybody else experienced this seeming cooperation between AI civs at war with each other? I was really pissed, but next time I will be better prepared.