Cantacuzene, i. p. 305; iv. pp. 290, 291; Nicephorus Greg., ix. p. 420, etc. Footnote 510: Phrantzes, p. 280. Footnote 511: Nicetas Chon., p. 269. Footnote 512: See Benjamin of Toledo, and Odo de Dogilo, iv. p. 37, both of whom visited the palace in the reign of Manuel Comnenus. Footnote 513: Cantacuzene, i. pp. 89, 90. Footnote 514: See Map facing p. 115. Footnote 515: Cantacuzene, iii. pp. 611, 612; Nicephorus Greg., xv. pp. 774-779. [Illustration: Plan of the So-Called Prison of Anemas.] CHAPTER X. THE TOWER OF ANEMAS—THE TOWER OF ISAAC ANGELUS. The next portion of the walls to be considered, beginning at the tower marked with an inscription in honour of Isaac Angelus,[515] and terminating at the junction of the Wall of Heraclius with the Wall of Leo, has undergone many changes in the course of its history, and, consequently, presents problems which cannot be solved in the actual state of our knowledge. After all is said on the subject, there will be room for wide difference of opinion. Originally, it would seem, this portion of the walls formed part of the defences around the outlying Fourteenth Region of the city; later, it constituted the north-western front of the enclosure around the Palace of Blachernæ. It is remarkable for its dimensions, rising in some places 68 feet above the exterior ground-level, with a thickness varying from 33-¼ to 61-½ feet. Inside the city the ground reaches the level of the parapet-walk. The wall is flanked by three towers, the second and third being built side by side, with one of their walls in common. In the body of the wall behind the twin towers, and for some distance to the north of them, were three stories of twelve chambers, presenting in their ruin the most impressive spectacle to be found in the circuit of the fortifications. The first[516] of the three towers stands at the south-western angle of the enclosure around the Palace of Blachernæ, where the fortifications around the western spur of the Sixth Hill, to the rear of the Wall of Manuel, join the wall now under consideration; the tower’s upper chamber being on the level of the palace area. Upon the tower is the following inscription, in honour of the Emperor Isaac Angelus: ΠΡΟΣΤΑΞΙ ΑΥΤΟΚΡΑΤΟΡΟΣ ΑΝΓΕΛΟΥ ΙΑΣΑΑΚΙΟΥ ΠΥΡΓΟΣ ΕΚ ΠΑΡΑΣΤΑΣΕΩΣ ΔΙΜΕΗΙ ΒΑΣΙΛΕΙΟΥ ΕΤ ϚϠΧΙ (6696).[517] “Tower, by command of the Emperor Isaac Angelus, under the superintendence of Basil ... (?) in the year 1188.” The twin towers rise to a great height, and are supported along their base by a massive buttress or counter-fort, 1 G1 G2 G3 G4, that stands 23 feet above the present ground-level, and projects from 19-½ to 26 feet beyond the towers.