42/78 It ran uninterruptedly along the four sides, and was reached by narrow staircases formed in the thickness of the walls, but now destroyed. There was no ditch, but in order to protect the base of the main wall from sappers, they erected, about ten feet in advance of it, a battlemented covering wall, some sixteen feet in height. These precautions sufficed against sap and scaling; but the gates remained as open gaps in the circuit. It was upon these weak points that besiegers and besieged alike concentrated their efforts. The fortress of Abydos had two gates, the main one being situate at the east end of the north front (fig. |