Diaulos was a double-stadion

Stadion

Stadion or stade , was an ancient running event, part of the Olympic Games and the other Panhellenic Games. It was one of the five major Pentathlon events. It was the premier event of the gymnikos agon...

 race (ca. 400 m.) introduced in the 14th Olympiad

Olympiad

An Olympiad is a period of four years, associated with the Olympic Games of Classical Greece. In the Hellenistic period, beginning with Ephorus, Olympiads were used as calendar epoch....

 of the ancient Olympics (724 BC). Scholars debate whether or not the runners had individual "turning" posts for the return leg of the race, or whether all the runners approached a common post, turned, and then raced back to the starting line.

Sources

• Miller, Stephen G. Ancient Greek Athletics: the events at Olympia, Delphi, Nemea, and Isthmia. Yale University Press, 2004. ISBN 0300115296
• Golden, Mark. Sport in the Ancient World from A to Z. Routledge, 2003. ISBN 0415248817