The earliest human occupation on the hill goes back to the Neolithic period (about 5000 B.C.). It was followed by successive settlements but their remains have been destroyed almost completely by the extensive construction arrangement of the Mycenaean age. Enough evidence survived from the settlement of the Early Bronze Age (2500-2000 B.C.) to prove the existence then of a series of apsidal houses arranged around a very huge circular building (diam. 28 m) on the summit of the hill.
The building of the fortification of the hill began during the 14th century B.C. and was completed at the end of the 13th century (Late Helladic IIIB period). The Cyclopaean walls which surround the Upper, Middle and Lower Citadel, have a total perimeter of approximately 750 m and a width between 4,50 and 7 m. Within the walls were planned the wall-painted palace, the remaining public spaces, the cyclopaean tunnels leading to the storehouses and the workshops. The town divided into blockhouses extended outside the walls and around the Acropolis (about 750 acres).