The city about to be besieged is situated on a peninsula at the south-west extremity of the Bosporus. It is, roughly speaking, an isosceles triangle with its base to landward. One of the sides is bounded by the Marmora and the other by the Golden Horn. It was surrounded by walls, which, with a few short intervals, still remain. On the two sides bounded by the sea they were built close to the water’s edge. In the course of centuries the Golden Horn had silted up a deposit of mud which even before 1453 formed a foreshore outside the north walls of a sufficient extent to have allowed Cantacuzenus to open a foss from Seraglio Point to Aivan Serai, formerly known as Cynegion. The side of the triangle most open to attack was that which faced the land and extended from the Horn to the Marmora. The walls on this landward side, constructed mainly during the reign of Theodosius the Second, had proved themselves during a period of a thousand years sufficiently strong to have enabled the citizens successfully to resist upwards of twenty sieges, and previous to the introduction of cannon were justly regarded as invulnerable.[240]
The landward walls are four miles long. From the Marmora to a point where the land has a steep slope for about half a mile down to the Golden Horn, they are triple. The inner and loftiest is about forty feet high and is strengthened by towers sixty feet high along its whole length and distant from each other usually about one hundred and eighty feet. Outside this wall is a second, about twenty-five feet high, with towers similar to though smaller than those along the inner wall. This wall alone is of a strength that in any other mediaeval city would have been considered efficient.
Between these two walls was the Peribolos or enclosure, which, though of varying width, is usually between fifty and sixty feet broad. Outside the second was yet another wall, which was a continuation in height of the scarp or inner wall of the ditch or foss and which may conveniently be called a breastwork. This breastwork, like the other two, was crenellated. Though, from the fact that it has been easier of access than either of the others, the summit has mostly perished, some portions of it are still complete. It is important, however, to note that the third wall or breastwork is disregarded by contemporary writers, and that they speak of the second as the Outer Wall. A second enclosure, called by the Greeks the Parateichion to distinguish it from the Peribolos, exists between the second and the third walls. The foss or ditch, which has withstood four and a half centuries of exposure since it last served as the first line of defence, is still in good condition. It has a width of about sixty feet.
The landward wall contained a number of gates which are conveniently described as Civil Gates and which during times of peace gave access to the city over bridges which were destroyed when it was besieged. The most important of these for our present purpose are the Chariseus, the modern Adrianople Gate; Top Capou or Cannon Gate, known in earlier times as the St. Romanus Gate, and the Pegè or Gate of the Springs, now called Silivria Gate. Besides these there were Military Gates leading from the city through the inner wall into the enclosures which were known in earlier times by their numbers (counting from the Marmora end of the walls) or from the division of the army stationed near them. The most noteworthy of these were the Third or Triton and the Fifth or Pempton. The latter is in the Lycus valley, about halfway between Top Capou and the Gate of Adrianople, and was spoken of during the siege as the St. Romanus Gate.[241]
As the most important military events in the history of the siege of Constantinople took place in the valley of the Lycus, between the Top Capou on the south and the Adrianople Gate on the north of the valley, it is desirable that the configuration of the locality should be noted carefully. Each of these gates is upon the summit of a hill, the Adrianople Gate indeed being the highest point in the city and, as such, having had near it, as is the almost invariable rule in lands occupied by Greeks, a church dedicated to St. George, who took the place of Apollo when the empire became Christian.[242] Between the two gates exists a valley, about a hundred feet below their level, which is drained by a small stream called the Lycus. The distance between the two gates is seven eighths of a mile. The double walls of Theodosius connect them, while in front of the Outer Wall was an enclosure with the usual breastwork forming the side of the foss. The Lycus enters below these walls through a well-constructed passage still in existence, and flows through the city until it empties itself into the Marmora at Vlanga Bostan. The tower beneath which it has been led is halfway between the Adrianople Gate and Top Capou. About two hundred yards to the north of this tower is the Fifth Military Gate or Pempton, spoken of sometimes by the Byzantines as the Gate of St. Kyriakè, from a church within the city which was close to it, called the Romanus Gate by the writers on the siege, and on old Turkish maps described as Hedjoum Capou or the Gate of the Assault.[243] The foss has a number of dams at irregular distances down each side of the valley. In its lowest part no dams were necessary.[244]
The walls between Top Capou and the Adrianople Gate were known as the Mesoteichion, and the name seems to have been applied also to the whole of the valley. The portion of the walls on either side of the Adrianople Gate, or perhaps those only on the high ground to the north of it, was known as the Myriandrion—a name which was applied occasionally to the Gate itself. From a tower to which Leonard gives the name Bactatinian, near where the Lycus entered the city, to Top Capou, the walls were described as the Bachaturean.
Approximate Restoration of the Land Walls of Theodosius the Second between the Golden and Second Military Gates.
Scale of Metres.
This photograph shows the present condition of a portion of the Landward Walls. They remain for the most part in an equally good state of preservation. The Inner and the Second, usually called the Outer, Wall and the Foss (now without water) are clearly shown. The Third Wall or Breastwork has lost its upper portion and its crenelations, except in a few places. The photograph is reproduced from one by M. Irenian, of Constantinople.