After crossing the low hills east of the Pyramus it passed through a masonry (Cilician) gate, Demir Kapu, and entered the plain of Issus.
The Serbian cavalry descending the Vardar had not yet passed the defile of Demir Kapu, the Serbian armies were being rearranged for the new movements above detailed, and even the I.
Whence the cavalry with infantry support was sent to seize Demir Kapu.
The 1st hill is distinguished by the Seraglio, St Sophia and the Hippodrome; the 2nd by the column of Constantine and the mosque Nuri-Osmanieh; the 3rd by the war office, the Seraskereate Tower and the mosque of Sultan Suleiman; the 4th by the mosque of Sultan Mahommed II., the Conqueror; the 5th by the mosque of Sultan Selim; the 6th by Tekfour Serai and the quarter of Egri Kapu; the 7th by Avret Tash and the quarter of Psamatia.
Accordingly, in 413, in the reign of Theodosius II., Anthemius, .then praetorian prefect of the East and regent, enlarged and refortified the city by the erection of the wall which forms the innermost line of defence in the bulwarks whose picturesque ruins now stretch from the Sea of Marmora, on the south of Yedi Kula (the seven towers), northwards to the old Byzantine palace of the Porphyrogenitus (Tekfour Serai), above the quarter of Egri Kapu.