Quote Originally Posted by Clearchus
You need 8 units and a general in an army. Click to get the character information scroll for the general, and there should be a button near the bottom that says "join crusade" if I remeber correctly. Obviously, click that.
Actually it only has to 8 units, the general counts as 1. So far my crusades have been a general 6 infantry units (missile and light cav usually) plus a siege engine. Other infantry types and heavy cav can be goten hold of as crusader mercs and regular mercs.