...when Emperor Napoleon's army attacked General Kutuzov's army, but lost since all of Napoleon's neighboring armies joined the battle one by freaking one only after Napoleon's main forces were defeated and routed? Yeah Empire Total War remembers!
Possibly the most stupid way of multiple armies joining a single battle ever.
"Oh yeah guys, sorry we can't enter the battle until some of you get routed or killed! But good luck!" - No real soldier/general ever.
Anyone know of a good way to make all your units join a single battle, without them having to wait for the main force to be wiped out to join?