A small island near Athens
which stood in the centre of a long dispute (and several wars) first between Megara
, and then between Athens
In the Iliad the island is described as the birthplace of Aias (aka Ajax), who lead the "Athenian People" to Troy. This quotation was one of the bases of the Athenian claim of the island. The real reason, however, was that the island completely controlled the entrance to Piraeus, the most important port of Athens. Athens eventually occupied and controlled the island.
During the Persian Wars (the beginning of the 5th century BC), when the Athenians discovered that their allies (the leader of the Greek forces was Sparta) were not going to help them defend the city, and knowing that the city (which did not have good walls) could not
survive a siege, Themistocles advised them to abandon the city and Attica and move all the women, children and anyone else not fighting to Salamis, stating that a polis is not earth, walls and buildings, but rather it is its citizens.
Salamis was later the site of the amazing victory of the Athenian and Greek navy over the Persian one, which was demolished and crushed beyond repair). Although there was one more battle in the war (in Plataea), the war was already won with the Battle of Salamis.