The castle of Chora on Kalymnos spreads on the broad top of a steep hill a short distance to the NE of the settlement of Chora, 255 metres above sea level. Its walls encircle an area of 3 hectares. They contain a densely built medieval settlement consisting of mostly small houses, some single-storey and others with a second floor in ruinous condition. There are also ten small churches which are well preserved, most with post-Byzantine murals. The castle dates from the middle Byzantine period (10th-12th c.) In the Hospitaller period (1309-1522) it expanded and was partially rebuilt in the late 15th century. The masonry of the fortifications is irregular, with a strong lime mortar, with battlements whose parapets are furnished with double-swallowtail merlons. The castle was inhabited throughout the succeeding Ottoman period until the early 18th century, when it was gradually abandoned, the population settling on the slope below the castle to form the Chora.