It is also called Agia Marina Castle and it is located on northeast Leros, at the Panteli bay. The Knights of Saint John did some important fortification work which is denoted by the four banners found in various points of the castle. On the west side of the castle lies the 18th century Church of Panagia, while inside the temple there is an Ecclesiastical museum with rare religious manuscripts, utensils, vestments, icons, etc. In the second courtyard of the castle there are two more abandoned churches which were built somewhere between 1306 and 1492.