History of the Peloponnesian War
Thucydides
Thucydides, Vol. 1-4. Smith, Charles Foster, translator. London and Cambridge, MA: Heinemann and Harvard University Press, 1919-1923.
During the same winter the Athenians purified Delos in compliance with a certain oracle. It had been purified before by Peisistratus the tyrant,[*](First tyranny 560 B.C.; death 527 B.C.) not indeed the whole of the island but that portion of it which was visible from the temple; but at this time the whole of it was purified, and in the following manner.
All the sepulchres of the dead that were in Delos they removed, and proclaimed that thereafter no one should either die or give birth to a child on the island, but should first be carried over to Rheneia. For Rheneia is so short a distance from Delos that Polycrates the tyrant of Samos, who for some time was powerful on the sea and not only gained control of the other islands[*](The Cyclades.) but also seized Rheneia, dedicated this island to the Delian Apollo, and bound it with a chain to Delos.[*](“As a symbolical expression of indissoluble union” (Curtius).) It was at this time, after the purification, that the Athenians first celebrated their penteteric[*](ie. celebrated every fifth year.) festival in Delos.
There had indeed in ancient times been a great gathering at Delos of the Ionians and the inhabitants of the neighbouring islands; and they used to resort to the festival with their wives and children, as the lonians now do to the Ephesian games; and a contest was formerly held there, both gymnastic and musical, and choruses were sent thither by the cities.