It's use was demonstrated by Rashad Evans as part of Alexander the Great's arsenal.
As its name suggests, Pankration is a hybrid martial art, combining techniques from ancient boxing and wrestling, but also using kicks, arm locks, and chokeholds. It is often compared as the forerunner of modern-day Mixed Martial Arts (MMA). Ancient Pankration only banned the use of eye-gouging and biting. Contests had no time limits, and usually were stopped when one Pankratiast submitted, signalling his defeat by raising his index finger. Because this was seen as the ultimate humiliation, it was not uncommon for fighters to refuse to submit, even at the expense of their lives.
In Ancient Mythology, both Heracles (better known as Hercules) and Theseus are credited with creating pankration, due to using pankration techniques to defeat supernatural monsters (Heracles defeating the Nimean Lion, and Theseus killing the Minotaur). However, it is more likely that it evolved due to a desire to have a new sport which used all fighting techniques, something neither boxing or wrestling alone could do. It first appeared in the ancient Olympic Games in 648 BC, and quickly became the most popular sport at the Games.
In addition to its sporting aspects, pankration was widely used by the Greeks as a form of unarmed combat. Both the Spartan hoplites and Alexander the Great's army used pankration when they found themselves unarmed in the heat of combat. Even after Greece was conquered by the Romans, pankration survived, adopted by the Romans as a companion sport to gladiatorial combat. However, both gladiators and pankration fell victim to the rise of Christianity, as both were seen as savage pagan rituals.
In 1896, the modern Olympic Games were formed. The Cardinal of Lyon voiced his opinions of the ancient martial art to Pierre de Coubertain, the founder of the modern Olympic Games, by saying "We accept all [events to be reinstated], except Pankration."
Pankration has seen a revival in modern times, though stripped of many of its more brutal qualities. With the rising popularity of mixed martial arts, there has been talk of entering it in the modern Olympic Games, possibly under the name Pankration.