Palaio Pyli

Palaio Pyli is an inland Byzantine citadel near the centre of Kos, about nine kilometres from the coast, perched on a hill 360 metres high. The site may have been fortified as early as Mycenaean times, judging by a traced wall section on the north-west slope and cyclopean masonry remnants on the north-east. The castle itself was founded in the 11th century by the monk Hosios Christodoulos, who also established the monastery of Saint John on Patmos. It remained inhabited through the Knights' period (1315-1522) and after the Ottoman conquest, until a plague around 1830 prompted its abandonment.

The fortifications comprise three baileys: the upper rings the summit, the second encloses a wider area to the east, west and south, and low wall remnants to the north suggest a third. Seven towers survive in total, four in the first bailey and three in the second, with gates at three points. The most striking feature is a square Byzantine gateway flanked by four semicircular arches. Inside, a rectangular building of roughly five by six metres stands complete in the north-west corner, though altered and undated, with a flat roof and a single entrance facing the bailey interior. A large underground cistern occupies the centre, and a post-1522 building sits to the south-east.