McAllister, P., Manthropology, 2010
In 648 BCE a no-holds-barred combat sport event called Pankration "All Powerful" or "Anything Goes," was introduced to the Greek Olympic Games, eventually becoming so popular that it was turned into the games' finale. The Pankration was a brutal striking and grappling fight with no time limits, no weight divisions, and just two rules: no eye gouging and no biting (the Spartans, true to form, permitted even these). Everything else was allowed -- breaking limbs, strangulation, fish-hooking (inserting fingers into orifices and ripping), and the wrenching and breaking of fingers and toes. (A Greek vase dated to 520 BCE, for example, clearly shows one pankratiast kicking another in the testicles.) A careful reading of Greek literature shows that, as far as the Pankration was concerned, the "ultimate" tag was, in this case, completely justified: ancient pankratiasts really did often pay the ultimate price for entering the arena.
A volume of Olympian Odes by the sixth-century BCE Greek poet Pindar, for example, records that "very many [pankratiasts] died in the contests." A more specific reference is found in the later works of Philostratus, who records a letter from a trainer to his pankratiast pupil's mother, telling her that "many times [wrestlers and pankratiasts] endured to the death." Philo even cites the amazing tale of two pankratiasts who attacked each other so ferociously that both died simultaneously. This is possibly exaggeration, since Philo doesn't claim to have witnessed the fight himself, yet there is one undeniably genuine instance of a pankratiast dying just as he secured victory: the case of Arrichion, a three-time victor of the Olympic Pankration, who won his third crown by surviving strangulation just long enough to dislocate or break his opponents ankle (the sources here are unclear) but then died. Judges crowned his corpse the winner. Given that all these references were to deaths that took place at the actual Olympics (which, though famous, were just one of a multitude of Greek games at which the Pankration was fought), it seems likely that the mortality rate in ancient Greek ultimate fighting was very high indeed.
Perhaps the final proof of its lethality, though, is the feared pankriatist Dioxippus, who in 336 BCE won by default since nobody dared even to get in the arena with him. Clearly, would-be competitors understood that losing to this champion meant not just defeat but probably death.
Incredibly, however, Pankration was not even the most lethal ancient Greek Olympic combat sport. That honor, as in modern times, goes to boxing. One competitor in both the Pankration and the boxing, Kleitomachos of Thebes, for example, asked Olympic officials to hold the boxing after the Pankration, since he had a greater chance of being wounded or killed in the former than in the latter. Once again, the ancient Greek literature confirms the concerns were only too well founded. Four definite references to deaths in Greek athletic boxing have come down to us (the true number was certainly many more), some of them stunningly gruesome. One work by Greek writer and geographer Pausanias, for instance, describes the victory (but then disqualification) in the 496 or 492 BCE Olympic Games of the boxer Cleomedes, who killed his opponent, Iccus, by driving his hand into his stomach and disemboweling him.
... But perhaps the final proof of Cleomedes' gory feat is the fact that the very same thing happened again a century later (this time at the Nemean Games) when a boxer called Damoxenus killed his opponent, Creugas, in a penalty punchoff after a grueling, day-long struggle, with another disemboweling spearhand to the gut.