Thank you all for answering. I will consider downloading after I finish my current campaign so I have no worries about messing up any savegames. The Mamluks were attacking four ranks deep by the way.

I heard there was a patch that helped reduce casualties by routing units. I really hate it when I flank a spear unit with my cavalry, then have the routing spears massacre my flanking units. I really want to try that Napoleon mod, sounds really cool.