Balcony in the Southern Façade of the Palace of the Porphyrogenitus.
That the western spur of the Sixth Hill was a fortified position early in the history of the city can scarcely be disputed. It must have been so, to commence at the lowest date, before the erection of the Wall of the Emperor Manuel in the twelfth century; for it was to get clear of the fortifications on that spur that the Comnenian Wall describes the remarkable detour it makes in proceeding from the court of the Palace of the Porphyrogenitus towards the Golden Horn, running out westwards for a considerable distance before taking a northerly course in the direction of the harbour. Then, there is reason to believe that the spur was fortified as early as the seventh century. This is implied in the accounts we have of the siege of Constantinople by the Avars in 627, when we hear of fortifications, named the Wall of Blachernæ,[[457]] the Pteron[[458]] or Proteichisma,[[459]] outside of which stood the Church of Blachernæ and the Church of St. Nicholas.[[460]]
Archway leading to the Gate of the Xylokerkus (Screen Tower). The Palace of the Porphyrogenitus (From The West).
For these sanctuaries were situated precisely at the foot of the western spur of the Sixth Hill, the site of the former being marked by the Holy Well of Blachernæ at Aivan Serai, that of the latter by the Holy Well in the ground between the Wall of Heraclius and the Wall of Leo.
It is also in favour of the presence of fortifications on the spur in the seventh century to find that the historians of the Avar siege are silent as to any danger incurred by the Palace of Blachernæ, which stood on the spur, when the Church of St. Nicholas was burnt down, and when the Church of Blachernæ narrowly escaped the same fate. A similar silence is observed as to any advantage derived by the palace from the erection of the Wall of Heraclius, at the close of the war.
But the age of these fortifications may be carried back to a still earlier date than the seventh century; for, according to the Notitia, the Fourteenth Region of the city, which stood on the Sixth Hill, was defended by a wall of its own, proprio muro vallata, so as to appear a distinct town.[[461]] The fortifications on the Sixth Hill may therefore claim to have originally constituted the defences of that Region, and therefore to be as old, at least, as the reign of Theodosius II.
But although the origin of the fortifications around the western spur of the Sixth Hill may thus be carried so far back, it is a mistake to regard them as a structural prolongation of the Theodosian Walls. On the contrary, they are distinct and independent constructions. They proceed northwards, while the latter make for the north-east; so that the Wall of Anthemius, if produced, would stand to the east of the former, while the Wall of the Prefect Constantine under similar circumstances would cut them transversely. Furthermore, the outer wall, north of the Kerko Porta, is built almost at right angles against the wall of the Prefect Constantine, with a distinct line of junction, and stands so close to the Kerko Porta that the gate, what with the wall on one side and the tower screening the western façade of the Palace of Porphyrogenitus[[462]] upon the other, is almost crushed between them. Such a situation could never have been assigned to the gate, if the walls on either hand belonged to the same construction. It should also be added that the masonry of the walls around the spur is different from that in the Walls of Theodosius.
How the non-Theodosian character of the walls to the north of the Kerko Porta is to be accounted for admits of more than one explanation. It may be due to changes in works of Theodosian origin, or to the fact that they are works of an earlier period,[[463]] or to the fact that they are works of a later age. On the supposition that these fortifications defended originally the Fourteenth Region, the second explanation is the most probable, for the division of the city into Regions was anterior to Theodosius II., and there is every reason to believe that the isolated Fourteenth Region was a fortified suburb from the earliest period of its history.[[464]]