Pankration
Pankration is a sport or martial art introduced in the Olympic games in 648 BC. It combined striking and grappling, and a match would be won by submission of the opponent. A contestant could signal submission by raising his hand, but sometimes the only form of submission was the death of one of the contestants. Joint locks and choke holds were common techniques of accomplishing this. In fact, there were only two rules: contestants were not allowed to gouge each other's eyes out, or to bite each other. The ancient Olympics also had a less violent pankration contest for young boys.
Pankration striking was somewhat crude. Large swinging kicks and punches were the method of attack, relying heavily on strength. For this reason, Pankration was the domain of the heavier athletes.
Ancient sculptures and pottery paintings depicting naked pankration fighters show blade-like hands and crouches reminiscent of modern martial arts.
Among pankration fighters, Dioxippus was the most famous. He won several Olympic games as no one dared challenge him. He became friends with Alexander the Great, and was challenged by one of Alexander's soldiers named Coragus. Coragus fought with weapons and full armour, but was still defeated by the unarmed Dioxippus; Alexander was ashamed for his army and forced Dioxippus to commit suicide.
In the lead-up to the 2004 Athens Olympic Games, a modern version of pankration was tipped as being a new sport in the Olympiad, significantly in regards to its being an event in the ancient games. However, its application (along with that of inline skating) was not approved. Rumours being that it was knocked back due to its inherently violent nature, even though the modern version is obviously significantly more watered-down than the original - to the point that other sports like boxing and wrestling would possibly have just much, if not more, injury and blood - and new rules could have been developed specifcally governing Olympic competition of the event.
The reasons for its being knocked back were more likely twofold: economy (as new sports cost money), and the fact that staging the event would be a double-edged sword in regards to the Olympics' professional, peace-loving image. The re-introduction of a sport from the ancient games would not go unnoticed by the media, but then neither would the fact that it was originally a bloodsport, despite the fact that there are an international set of humane rules governing the sport. (Boxing and wrestling have not caused such controversy because they are sports that have consistently been competed in, and their rules have gradually evolved over the thousands of years they have existed.) Such controversy is inherent to all mixed martial arts, and is often born of ignorance of the workings of the sport itself. The same is true for pankration - in many ways, the oldest known hybrid martial art.