 The Return of the Heracleidae, which is the closest event to a Dorian Invasion available in legend, must coincide with the entry of Aristodemus and his brethren into Arcadia, which, based on the chronology of Eratosthenes, happened 328 years before the generally accepted date of the first year of the first Olympiad, 776 BC.Eratosthenes' date is therefore 1104 BC.This must be the year of Aristodemus' military activity in Arcadia, his fatherhood and his assassination.