Rumelihisar? (also known as Rumelian Castle and Roumeli Hissar Castle1) is a fortress located in the Sar?yer district of Istanbul, Turkey, on a hill at the European side of the Bosphorus. It gives the name of the quarter around it. It was built by the Ottoman Sultan Mehmed II between 1451 and 1452, before his army’s conquest of Constantinople. The three great towers were named after three of Mehmed II’s viziers: Sadrazam Çandarl? Halil Pasha, who built the large tower next to the gate; Za?anos Pasha, who built the south tower; and Sar?ca Pasha, who built the north tower.