In the later 4th century the name survives only (a) as a geographical expression for part of the coast of Asia Minor, (b) in European Greece as the name of that section of the Northern Amphictyony in which Athens and its colonies were reckoned.
Under the dominion of the Roman republic its national league was dissolved, but was revived by Augustus, who also restored to Phocis the votes in the Delphic Amphictyony which it had lost in 346 and enrolled it in the new Achaean synod.
For the history of the Delphic Amphictyony see under Amphictyony.
Olympia thus became the centre of an amphictyony, or federal league under religious sanction, for the west coast of the Peloponnesus, as Delphi was for its neighbours in northern Greece.
It suited the interests of Sparta to join this amphictyony; and, before the regular catalogue of Olympic victors begins in 77 6 B.C., Sparta had formed an alliance with Elis.
The victorious Greeks subsequently punished Thebes by depriving it of the presidency of the Boeotian League, and an attempt by the Spartans to expel it from the Delphic amphictyony was only frustrated by the intercession of Athens.
After the Persian wars, the predominance of Athens led to the transformation of the Delian amphictyony into the Athenian empire.
At the close of the Peloponnesian War the Spartans gave to the people of Delos the management of their own affairs; but the Athenian predominance was soon after restored, and survived an appeal to the amphictyony of Delphi in 345 B.C. During Macedonian times, from 322 to 166 B.C., Delos again became independent; during this period the shrine was enriched by offerings from all quarters, and the temple and its possessions were administered by officials called i€poirocol.
(On the Delphian cult of Apollo and its political significance, see Amphictyony, Delphi, Oracle; and Farnell, Cults, iv.
The ancient Calauria, with which Poros is identified, was given, according to the myth, by Apollo to Poseidon in exchange for Delos; and it became in historic times famous for a temple of the sea-god, which formed the centre of an amphictyony of seven maritime states' - Hermione, Epidaurus, Aegina, Athens, Prasiae, Nauplia, and Orchomenus.