Ialysos, Archaeological site on Mount Filerimos, Rhodes, Greece.

Ialysos is an ancient city on Mount Filerimos in Rhodes containing ruins spanning multiple periods, including a Doric temple, medieval fortifications, and a monastery on the hilltop. The remains represent more than 3,000 years of human settlement and religious worship at this strategic location.

The settlement began around 1550 BC and was one of Rhodes' first organized centers with a sanctuary dedicated to the goddess Athena. Later Byzantine and medieval rulers built their own structures over the older remains, reshaping its appearance and purposes over centuries.

The site served as a major sanctuary that drew worshippers from across the region to participate in religious ceremonies and rituals. The layered religious structures show how successive populations expressed and overlaid their own spiritual beliefs at this sacred location.

The ruins lie on the slopes and summit of Mount Filerimos above modern Ialysos (Trianta). The hilltop is exposed, with little shade, so bring water and sun protection for the climb. Ground is rocky and uneven, with steps between the fountain terrace, the temple foundations and the medieval walls; sturdy shoes help.

Beneath the south slope of the acropolis stood a monumental fountain of the 4th century BC, fed by a spring through two spouts carved as lion heads. Its water poured into a wide basin edged by a parapet of pillars and carved slabs, also with lion-head spouts, and six Doric columns formed its facade. It was reused in medieval times, buried by a collapse, and dug out again in 1923.