OLYMPIAD, in Greek chronology, a period of four years, used as a method of dating for literary purposes, but never adopted in every-day life. The four years were reckoned from one celebration of the Olympian games to another, the first Olympiad beginning with 776 B.C., the year of Coroebus, the first victor in the games after their suspension for 86 years, the last with A.D. 394, when they were finally abolished during the reign of Theodosius the Great. The system was first regularly used by the Sicilian historian Timaeus (352–256 B.C.).