Eleusis, the most famous *deme in Athens after *Piraeus, on a land-locked bay with a rich plain, was a strong prehistoric settlement but merged with Athens sometime before the 7th cent. bce. Its hill (called Akris) and sanctuary were enclosed by fortification walls in the late 6th century, and it became one of the three main fortresses for the defence of western *Attica (with Panakton and *Phyle). There was an important theatre of *Dionysus there, and the sanctuary of *Demeter and Kore (see persephone) was the site of many festivals of local or national importance (*Eleusinia, *Thesmophoria, Proerosia, *Haloa, Kalamaia), but the fame of Eleusis was due primarily to the annual festival of the *mysteries, which attracted initiates from the entire Greek-speaking world. Within the sanctuary of the Two Goddesses the earliest building that may be identified as a temple is geometric. Its replacement by increasingly larger buildings (two in the Archaic period, two attempted but not completed in the 5th cent.), culminating in the square hall with rock-cut stands built under *Pericles (1), the largest public building of its time in Greece, bears eloquent witness to the ever increasing popularity of the cult.