The Ancient Olympic Games were religious and athletic festivals held every four years at the sanctuary of Zeus in Olympia, Greece. Competition was among representatives of several city-states and kingdoms of Ancient Greece. These Games featured mainly athletic but also combat sports such as wrestling and the pankration, horse and chariot racing events. It has been widely written that during the Games, all conflicts among the participating city-states were postponed until the Games were finished. This cessation of hostilities was known as the Olympic peace or truce. This idea is a modern myth because the Greeks never suspended their wars. The truce did allow those religious pilgrims who were travelling to Olympia to pass through warring territories unmolested because they were protected by Zeus. The origin of the Olympics is shrouded in mystery and legend; one of the most popular myths identifies Heracles and his father Zeus as the progenitors of the Games. According to legend, it was Heracles who first called the Games "Olympic" and established the custom of holding them every four years. The myth continues that after Heracles completed his twelve labours, he built the Olympic Stadium as an honour to Zeus. Following its completion, he walked in a straight line for 200 steps and called this distance a "stadion" (Greek: στάδιον, Latin: stadium, "stage"), which later became a unit of distance. The most widely accepted inception date for the Ancient Olympics is 776 BC; this is based on inscriptions, found at Olympia, listing the winners of a footrace held every four years starting in 776 BC. The Ancient Games featured running events, a pentathlon (consisting of a jumping event, discus and javelin throws, a foot race, and wrestling), boxing, wrestling, pankration, and equestrian events. Tradition has it that Coroebus, a cook from the city of Elis, was the first Olympic champion.
The Olympics were of fundamental religious importance, featuring sporting events alongside ritual sacrifices honouring both Zeus (whose famous statue by Phidias stood in his temple at Olympia) and Pelops, divine hero and mythical king of Olympia. Pelops was famous for his chariot race with King Oenomaus of Pisatis. The winners of the events were admired and immortalised in poems and statues. The Games were held every four years, and this period, known as an Olympiad, was used by Greeks as one of their units of time measurement. The Games were part of a cycle known as the Panhellenic Games, which included the Pythian Games, the Nemean Games, and the Isthmian Games.
The Olympic Games reached their zenith in the 6th and 5th centuries BC, but then gradually declined in importance as the Romans gained power and influence in Greece. While there is no scholarly consensus as to when the Games officially ended, the most commonly held date is 393 AD, when the emperor Theodosius I decreed that all pagan cults and practices be eliminated. Another date commonly cited is 426 AD, when his successor, Theodosius II, ordered the destruction of all Greek temples.