What is the basis for the claim that the ancient Greeks were skilled navigators?

The ancient Greeks first began to populate the Aegean coast. The warm, humid climate allowed them to practice gardens and agriculture. The endless expanses of the sea not only supplied the Greeks with fish, but also attracted them to distant lands. The Aegean Sea is calm and in its vastness there are chains of islands with cozy bays. Having learned how to make good-quality ships, the Greeks from island to island reached the shores of Asia Minor. Excellent shipbuilders and successful sailors, the ancient Greeks began to develop the northern lands and establish Greek policies there.