The language of Zosimus, taken alone, suggests, indeed, the idea that the gate of Byzantium had occupied a site to the west of the Forum; in other words, that the Forum was constructed to the east of the gate, within the line of the wall of Severus. For, according to the historian, one entered the porticoes of Severus and left the old town, after passing through the arches (δι᾽ ὧν) which stood, respectively, at the eastern and western extremities of the Forum of Constantine. This was possible, however, only if these various structures, in proceeding from east to west, came in the following order: Forum of Constantine; porticoes of Severus; gate of Byzantium. On this view, the statement that the Forum was “at the place where the gate had stood” would be held to imply that the porticoes between the Forum and the gate were too short to be taken into account in a general indication of the Forum’s position. But to interpret Zosimus thus puts him in contradiction, first, with Theophanes, as cited above; secondly, with Hesychius Milesius,[20] who says that the wall of Byzantium did not go beyond the Forum of Constantine (οὐκ ἔξω τῆς ἐπωνύμου ἀγορᾶς τοῦ βασιλέως); thirdly, though that is of less moment, with the Anonymus[21] and Codinus,[22] who explain the circular shape of the Forum as derived from the shape of Constantine’s tent when he besieged the city. Lethaby and Swainson[23] place the Forum between the porticoes of Severus on the east and the gate of Byzantium on the west, putting the western arch of the Forum on the site of the latter. They understand the statement of Zosimus to mean that a person in the Forum could either enter the porticoes _or_ leave the old town according as he proceeded eastwards or westwards. From that gate the wall descended the northern slope of the hill to the Neorion, and thence went eastwards to the head of the promontory.[24] In descending to the Golden Horn the wall kept, probably, to the eastern bank of the valley of the Grand Bazaar, to secure a natural escarpment which would render assault more difficult.