Thought I would just get the win, going through all 9 conquests (wanna see the victory movie!) But the Middle Ages are so interesting that I'm playing it again...
My first was Byzantium, that was a good easy start - it was fun to take Jerusalem and vaporize the Abbasids!

(The royal elimination adds a good twist - killing the 3rd king is easier than stomping out every last little town. Another example of the well-crafted variety of the Conquests, and a tad easier than the 8 cities in FoR.)
Now I'm playing Germany, and cleaning up Burgundy, who attacked me. They're a prime opponent, stretched long and thin - once you cut them in two, the capital is isolated in the north, making their southlands totally corrupt and ripe for the taking. Soon I'll have northern Italy and decide whether to go west into France or eastward. (Hmm, guess I'm a warmonger.)
Has anyone seen many treaties or alliances in this Conquest? It seems a striking difference after the recurrent dogpiles in Rise and Fall of Rome, where if you get attacked everyone else joins in, even those on the other side of the world. (Isn't it great when Egypt declares on the Celts, or Huns on Carthage? Several times per game??)
But here in the Middle Ages it seems safe to attack, since no other civ seems to care, even your neighbors, and those of the same religious persuasion as the foe... Perhaps historians could explain.