The temple of Zeus on the uppermost terrace is oriented towards the East. Its first phase is dated to the 4th century BC. Back then it was a prostylos with antae. In the second phase, a row of Ionic columns, 6 in front and 8 on the sides, as well as a second building behind the cella were added to align with the dimensions of the cella.
The colonnaded temple was sanctified by Idrieus, satrap of caria between 351 and 344 BC. Its details and general appearance resemble the temple of Athena in Priene, which indicates that both were built by the architect Pytheos.