Page:The age of Justinian and Theodora (Volume 1).djvu/49

 *astasius. A few paces further on is a Christian chapel dedicated to the Theotokos or Mother of God, founded by Pulcheria, the pious but imperious sister of Theodosius II, and finally the maiden wife of the Emperor Marcian. Hard by is a natural well, which from its interesting associations is now beginning to ripen into sanctity.

The scheme of fortification consists of three main defences: (1) a foss, (2) an outer wall with frequent towers, and (3) an inner wall, similar, but of much greater proportions.

(1) Since the moat necessarily follows the trend of the ground as it rises on either side from the beach to the dorsum of the peninsula, this canal, instead of maintaining a uniform level, consists of a number of sections divided by cross-*walls, the distances between which are determined by the exigences of ascent or descent. In its course it outlines the contour of the walls, which advance on the peninsula from each end in the form of a bow. The average width of this foss is about sixty, and its depth about thirty feet. It is lined on both sides from the bottom with substantial stone walls, but, whilst that on the outside only reaches the level of the ground, the wall next the city, with a crenellated top, rises for several feet, so as to convey the impression of a triple wall of defence. In peace time the water is allowed to run low, but if an assault is apprehended the trench can be quickly flooded by means of earthenware pipes concealed