The north-western coast of Anatolia was inhabited by Greeks of the Achaean/Mycenaean culture from the 20th century BC, related to the Greeks of southeastern Europe and the Aegean. Beginning with the Bronze Age collapse at the end of the 2nd millennium BC, the west coast of Anatolia was settled by Ionian Greeks, usurping the area of the related but earlier Mycenaean Greeks. Over several centuries, numerous Ancient Greek city-states were established on the coasts of Anatolia. Greeks started Western philosophy on the western coast of Anatolia (Pre-Socratic philosophy).