BC) Athens promised to restore to Aegina her autonomy, but the clause remained ineffective. During the first winter of the Peloponnesian War (431 BC) Athens expelled the Aeginetans and established a cleruchy in their island. The exiles were settled by Sparta in Thyreatis, on the frontiers of Laconia and Argolis. Even in their new home they were not safe from Athenian rancour. A force commanded by Nicias landed in 424 BC, and killed most of them. At the end of the Peloponnesian War Lysander restored the scattered remnants of the old inhabitants to the island, which was used by the Spartans as a base for operations against Athens during the Corinthian War. It is probable that the power of Aegina had steadily declined during the twenty years after Salamis, and that it had declined absolutely, as well as relatively to that of Athens. Commerce was the source of Aegina's greatness, and her trade, which seems to have been principally with the Levant, must have suffered seriously from the war with Persia. Aegina's medism in 491 is to be explained by its commercial relations with the Persian Empire. It was forced into patriotism in spite of itself, and the glory won by the Battle of Salamis was paid for by the loss of its trade and the decay of its marine. The loss of the state's power is explained by the conditions of the island, which was based on slave labour; Aristotle's estimated the population of slaves were as much as 470,000. Hellenistic period and Roman rule Aegina with the rest of Greece became dominated successively by the Macedonians (322–229 BC), the Achaeans (229–211 BC), Aetolians (211–210 BC), Attalus of Pergamum (210–133 BC) and the Romans (after 133 BC). A sign at the Archaeological Museum of Aegina is reported to say that a Jewish community was established in Aegina "at the end of the second and during the 3rd century AD" by Jews fleeing the barbarian invasions of the time in Greece. However, the first phases of those invasions began in the 4th century. The Romaniote jewish community erected an elaborate synagogue in rectangle form with an apse on the eastern wall with a magnificent mosaic decorated with geometric motifs, still preserved in the courtyard of the Archaeological Museum of Aegina. The synagogue dates from the 4th century AD and was in use until the 7th century AD. Local Christian tradition