Three things you didn't know about the history of the horse saddle

is hooked over the fixed head. For greater stability there is a leaping head under which the rider presses her upper left leg.
Show saddles are quite simply designed to show the conformation of the horse to best effect. They tend to have a long straight flap to expose the shoulder cleanly and no knee rolls.
Western saddles and stock saddles have a wider seat and cantle for comfort and a broader weight bearing area across the horses back.  They have wide stirrups and a horn at the front of the saddle which was originally used as an anchor point for roping cattle. The western saddle is secured to the horse but a cinch tied with a leather strap rather than a buckle.