One-third northward up the Bosphorus straits, on the western or European side, the castle stands to the north of Bebek (ancient Asomaton) and just below the site of the old Robert College, now Boğaziçi Üniversitesi (University of the Bosphorus). It was built on a north-south axis, shaped as a distended isosceles triangle, following the terrain it embraces, from shore up the hillside.1 Its curtain walls, fifteen meters high and over a meter thick, incorporate small towers and bastions, but its anchors are three major towers: at a central water entrance, and at north (Black Tower) and south corners (Rose Tower) on the hilltop. The fortress is 250 meters in north-south length, and from 50 to 100 meters in width, its highest (south) tower rising over 70 meters above water level. Interior structures included a large cistern and a mosque.
2. Historic Role
The castle overlooks an outcropping into Bebek Bay where the Bosphorus contracts to its narrowest point (700 meters)--a logical place for crossing the straits. Persian King Darius made a famous passage, on a campaign against the Scythians in 512 B.C., building his legendary bridge of boats to accommodate some 700,000 troops. Darius watched it all from a throne on the European side, cut in the rocks of the hill about where the present castle's north tower is situated. Another bridge of boats was created here for the Emperor Herakleios to cross to Constantinople in A.D. 636. Mehmet II's own father, Murad II (1421-1451), had crossed his army from Asia, on Genoese ships, en route to the Battle of Varna in 1444.
Mehmet himself noted the location at the beginning of his reign, in 1451, when, after campaigning in Anatolia, he wished to cross the Hellespont (Dardanelles) to his then-capital, Adrianople (Edirne) on the European side. Christian shipping blocked his passage at the time, and so, marching to the Bosphorus, he made his crossing without opposition at this narrow point. The young Sultan apparently recognized the locale as a choke-point, from which the Bosphorus could be controlled. Already, in the 1390's, in the first Turkish siege of Constantinople, Mehmet's great-grandfather, Sultan Beyazit I (1389-1403), had constructed a small fortress on the Asian side, known today as Anadolu Hisar (Eastern or Anatolian Castle), but then called by the Turks Akçe or Güzel Hisar ("White" or "Beautiful" Castle). Mehmet identified a site on the European side, exactly opposite, as the place for a corresponding, if more ambitious, fortress of his own. Through their control of the straits, he could threaten Constantinople's supply routes, clearly as a stage in his vision of making the old Byzantine city the Ottoman capital at last.
Planning intensively over the winter, Mehmet was ready by mid-March 1452. At Gallipoli, he mustered a flotilla of twenty-four war galleys and galliots plus sixteen supply boats, and sailed them to his chosen position. Local Christian buildings, including an old church of St. Michael on the site itself, were demolished for structural materials, augmented by shipments from elsewhere. A crew of some 5,000 laborers began work on April 15, and the Sultan introduced a competitive spirit, assigning the financing and construction of the fortress's great towers to his viziers, while he himself oversaw building of the connecting walls. The project's menace was clearly understood by the Emperor Constantine XI and his terrified citizens. There were ugly onsite scuffles between locals and the Turkish soldiers. Failing at diplomatic remonstrances, the Emperor was reduced to sending food and gifts to the workmen, only to have his final emissaries beheaded.
The construction was completed with astounding speed, by August 31, 1452. Before returning to Edirne, Mehmet installed a garrison of 400, and had mounted on the sea side three great cannon of unprecedented size, capable, it was said, of firing projectiles of up to 600 pounds. These weapons had been built by the renegade gun-maker Urban--who would design the cannon used soon after against the walls of Constantinople itself. With them in place, the Sultan proclaimed his control of the straits. He ordered all shipping subject to inspection and toll, on pain of destruction. Now, passage between the Aegean and Black Sea was crucial to the lucrative shipping of Italian merchants, especially the Genoese and Venetians, while vital for Constantinople's grain supply. Three Venetian ships defied the threat in early November. Two escaped the cannonade, but a third was sunk by direct hit. Its surviving crewmen were beheaded, and the captain, one Antonio Rizzo, was executed by impaling; the public exposure of their mangled bodies emphasized the Sultan's message. Rumeli Hisar thus confirmed its original Turkish name of Bogaz Kesen (Greek Laimokopia), translatable as either "Straits-cutter" or "Throat-cutter". The Sultan now turned his attention to organizing the epic siege of Constantinople itself, to begin the following spring.2
3. Later History
Rumeli Hisar was essentially a one-purpose monument. It placed a chokehold on Constantinople in its final Byzantine months, and served as one base for Turkish operations in the siege of 1453. Thereafter, domination of the Bosphorus was assumed by Turkish warships. Since Anadolu Hisar was seen as of no further use, it was allowed to fall into decay. Rumeli Hisar did serve for some time as a local garrison and as a prison, especially for foreign captives. But eventually it also fell into neglect, a village developing inside it. In 1953, for celebrations of the 500th anniversary of the capture of Constantinople, the old castle restored and made an accessible historic monument. The minaret's stump survives and the site of the old cistern has become an open-air theater where performances of the Istanbul Festival have been given. Meanwhile, the second (1988) of the two modern bridges crossing the Bosphorus has been built to the north, and named after the Conqueror.
1. The tradition that its design suggests the name of the Prophet, and of the Sultan himself, is unfounded.
2. Philippides M., Hanak W. The Siege and the Fall of Constantinople in 1453. Historiography, Topography, and Military Studies, Farnham, Ashgate, 2011, Chapter 7. A Castle and a Bombard. I. Rumeli Hisar: The Fortress of Doom, pp. 397-413