The Monastery of Saint George at the old armoury (the Mangana), built by Konstantinos Monomachos (1042-1055), was one of the richest monasteries of Byzantium. Because of its prominent position close to the cape in the east of Byzantium, the later Seraglio point, it was a well-known landmark for western sailers who called the Bosphorus "the arm of Saint George" since the thirteenth century. The monastery was destroyed some decades after the Ottoman conquest, and only those parts of its foundations where the railway does not go through have survived.