The Olympic festival, like the other Panhellenic festivals, was held once every four years in accordance to the Greek eight-year calendar. The exact dates of the festival were calculated on the basis of the lunar 28-day month. The games were held at the first full moon after the summer solstice, coinciding with today's mid-July, approximately between the 11th-16th of the month. This was the hottest period of the year, and many athletes found the heat uncomfortable.
The time spanning between two Olympic festivals was called an Olympiad. The term was also used to denote the days of the festival itself.
During the time interval between two Olympic festivals, Greeks gathered in other Panhellenic festivals held in other sanctuaries. The order of the festivals was the following:
|Date||Time of year||Event|
|540 BC||late summer||55th Olympiad|
|539 BC||summer||Nemean Games|
|538 BC||spring||Isthmian Games|
|537 BC||summer||Nemean Games|
|536 BC||spring||Isthmian Games|
|536 BC||late summer||56th Olympiad|
The Olympiads formed the basis of a nation-wide dating system. Each Olympiad
was named after the athlete who had won in that year's stadion race.
Later, in the early 4th century BC, the sophist Hippias of Elis numbered all Olympiads in
relation to the first Olympiad, held in
Introduction of Games | Events of an Olympiad