According to tradition and the testimony of ancient historians, Penthilios, the son of Orestes, led the Achaeans from Boeotia and Thessaly to Aeolis, whilst his descendants, the Penthilidae, reigned in Mytilene. In fact, the king of Cyme, Agamemnon, took this name to imply his descent from the race of Orestes.

From the finds of Protogeometric pottery in Lesbos and other cities of Aeolis it is concluded that settlement occurred in the period between 1050 and 900 BC. According to tradition, the colonists behaved like Achaeans, but the fact that Penthilios had led them from Boeotia and Thessaly and the name of the area in particular, show that most of them were Aeolians. Apart from Lesbos, Tenedos, Cyme and Mytilene, the area of Aeolis included Eressos, Temnos, Pitane, Myrina and Smyrna, the latter however was conquered by Colophonians and turned Ionian. The Aeolians were centred around the sanctuary of Apollo in Grynium.