Don't know about the Muslims. I'm playing the Russians and have turned off fog of war (I like to see what's going on elsewhere) and the Moors already have a big, big empire, while the Turks are gobbling up the Rebel provinces in the Southeastern corner.

The Scots could be a little more active, they seem to just sit there and wait for the English to come to them.
Hmm... Maybe I'll have to play as them after I finish with Russia.