Usually I chose Byz, and regular army is
2-5 Byz Inf.
1-2 Trebzoind Archers
1-3 Kats
2-4 spearmen

The Muslims usually have the advantage with horse archers, but in fighting Catholics, early, it its easy with the Byz Infantry, they are multi purpose (escpecially with the javelins) hehehehehe. The golden Horde is easy to defeat, if you have lots of cavalry, and some horse defeating foot soldiers, to take care of heavies and the mongol infatry.