The ancient Olympic games are one of the most studied institutions from classical antiquity, and they remain one of the most misunderstood. The sacred truce (ekecheiria) that was supposed to guarantee safe passage to athletes and spectators is one of the first documented international agreements in history, and it was largely observed for over a millennium.

The Games were not simply athletic competition — they were a religious festival in honor of Zeus at Olympia, and the athletic events were themselves forms of sacred offering. The olive crown given to victors was symbolically cut from the sacred olive grove at Olympia. The games were exclusive: Greek speakers only (with some flexibility at the edges as Greek culture spread), freeborn males only, no women as competitors or spectators in most events.

The professionalization of athletics was already underway in the classical period and generated exactly the complaints that modern sports generate: athletes who perform for prizes rather than glory, athletic guilds that negotiate appearance fees, class inequity in who can afford years of training. Pindar's odes celebrate aristocratic amateurism while the reality was already more complicated.

The games were suppressed by the Christian Roman emperor Theodosius I in 393 AD as part of his anti-pagan program. The modern Olympics, revived in 1896, bear only an ideological relationship to the ancient institution.