During the Peloponnesian War, Delos turned to Sparta for help against Athens. Sparta, using their unique form of logic, declined. If Delians could not be born or die on their island, then they were technically foreigners and Delos was not their homeland. Why help foreigners? Of course, Athens was not to pleased by the Delian overtures to their enemy and it was time for another purification. In 422 BC, the entire Delian poopulation was exiled to the Asia Minor. Delain leaders were executed. Exile only lasted for a year as war's misfortunes caused the Athenians to rethink their strategy and reverse policy, therby, hopefully pleasing the gods. Spartan victory brought better times to Delos, though the disagreements with Athens were never forgotten.
The Delian Alliance was ended with Macedonian predominance. Delos flourished becoming not only a religious center, but a center for commerce, as well. Many new buildings and new shrines were built during the Macedonian period. Rome defeated the Macedonians in 166 BC returning Delos to Athenian sovereignity. Of course, a fourth purification was called for and the Delians were exiled to Achaia. The purification was short-lived, though, with the fall of Corinth in 146 BC. Now, was Delos grandest period of commercial success, becoming one of the most important ports for east-west trade. People came here to live from all over the ancient world and were allowed to worship in their own separate ways - there is ruins of a synagogue, a sanctuary for both Syrian and Egyptian gods all from the same time frame of 2nd Century BC.
In many of the houses, you can see beautifully preserved mosaic floors from this Hellenistic-Roman period. Homes of the ancient worlds.