Medieval knights, when they weren't busy enganging in battles or protecting the interests of their lord, wanted to keep their skills honed, and often challenged rival knights to tournaments. These have their roots in lance and shield training conducted by Charlemagne's troops in the 8th and 9th centuries.
The first tournaments were mock battles that had more in common with military training than they did as a spectator sport. Jousting, where two knights would face each other atop horses, and armed with lances and shields, may have began as a way to settle disputes within the ranks. These early battles were called duels of chivalry. A knight won when he hit an opponent's shield or helmet. Striking the opponent's legs or hitting his horse was considered a foul. Jousting reached its height as a medieval spectator sport in the 13th century, where thousands would crowd the stands.
Sword fights with blunt blades were also part of the tournament. Most medieval weapons could have been used at some point in the competition, from battle-axes and maces to daggers and fists.
The winner often took the loser's horse and at times, his armor.