The superstructure was clay and the roof was made from fire-baked tiles. The first Greek inhabitants—the creators of the Middle Helladic civilization and the Mycenaean civilization after that—settled Tiryns at the beginning of the Middle period (2000–1600 BC), though the city underwent its greatest growth during the Mycenaean period. The Acropolis was constructed in three phases, the first at the end of the Late Helladic II period (1500–1400 BC), the second in Late Helladic III (1400–1300 BC), and the third at the end of the Late Helladic III B (1300–1200 BC). The surviving ruins of the Mycenaean citadel date to the end of the third period. The city proper surrounded the acropolis on the plain below.