During the period between 3200 BC - 2400 BC the Thermi area becomes a large coastal urban settlement (passing through five successive stages), with building blocks (town planning) and paved roads. The town is fortified. Other settlements have also been located on the island (the Kourtir settlement in Lisvori) while there are many smaller locations built on the fortified rocky hilltops, which possibly served as homes for the farmers and cattle-raisers. Stone tools (stone mills, spears etc.) and vessels reveal the purpose which these sites served. (Katapirgos of Lisvori and Aghia Paraskevi of Gera, Plati of Mistegna, Angourelia of Saracena, Saliakas, Podaras, Leperna, Koukla, Abasta, Makrina Pochi, Mosina, Dip, Kontisia, Skepasto, Kayia, Sourada, Tarti).

Lesbos belongs to the cultural sphere of North Eastern Aegean civilisation which encompasses Samos, Chios, Lemnos, Asia Minor (Troy), Thasos, Imbros, Samothrace, Thrace and Skyros.

During the Middle Bronze Age (2400-2000 BC) Thermi itself remains uninhabited but other sites are possibly inhabited (Kourtir - Hills).

During the Late Bronze Age (2000 - 1200BC) there are two successive settlements in Thermi and there may also be people living in other settlements.

In 1200 BC the Thermi settlement is destroyed. According to Homer, Lesbos takes the side of the Trojans in the war against the Achaeans. Few are the archaeological findings, which prove Mycenaean presence on the island (Makara and fragments of vessels found during excavation of the ancient cities).