Athens - Olympieion

A temple to the supreme god of the Greek pantheon, who had previously been worshipped in the open air, was built by Peisistratos on this site of Olympieion at some time before 550 B.C. - 100 years before the erection of the temple of Zeus at Olympia. It measured 30 by 60m/100 by 200ft - rather smaller than the later Parthenon.

The site, to the southeast of the Acropolis, then lay outside the city.

Peisistratos' sons Hippias and Hipparchos resolved to replace this temple by a gigantic new structure with a double colonnade (dipteros) measuring 41 by 107.75m/135 by 354ft, comparable with the temple of Hera built by Polykrates on the island of Sámos.

Work on this building, which was to have 8x21 columns, was suspended after the expulsion of Hippias in 510 B.C., and it lay unfinished for almost 350 years, until about 175 B.C., when the Syrian king Antiochos IV commissioned a Roman architect, Cossutius, to complete it.

The new temple was designed to have a double colonnade of 8x20 Corinthian columns, 17m/55ft high, of Pentelic marble; but this temple, too, remained unfinished, and it was not completed for another 300 years, until about A.D. 130, when Hadrian had it finished in accordance with Cossutius' plan. Its construction had thus taken 700 years altogether.
The Temple of Zeus is the most important monument of the Olympieion site.