The Wall of Leo stands 77 feet to the west of the Wall of Heraclius, running parallel to it for some 260 feet, after which it turns to join the walls along the Golden Horn. Its parapet-walk was supported upon arches, which served at the same time to buttress the wall itself, a comparatively slight structure about 8 feet thick. With the view of increasing the wall’s capacity for defence, it was flanked by four small towers, while its lower portion was pierced by numerous loopholes. Two of the towers were on the side facing the Golden Horn, and the other two guarded the extremities of the side looking towards the country on the west. The latter towers projected inwards from the rear of the wall, and between them was a gateway corresponding to the Heraclian Gate of Blachernæ.
The citadel formed by the Walls of Heraclius and Leo was designated the Brachionion of Blachernæ (τὸ Βραχιόνιον τῶν Βλαχερνῶν).[[569]] Subsequent to the Turkish Conquest it was named after the five more conspicuous towers which guarded the enclosure, the Pentapyrgion,[[570]] on the analogy of the Heptapyrgion, or Castle of Severn Towers (Yedi Koulè) at the southern end of the land walls.
Near the southern end of the wall, where it has evidently undergone repair, two inscriptions are found. One is in honour of Michael II. and Theophilus, the great Emperors:
ΜΙΧΑΗΛ ΚΑΙ ΘΕΟΦΙΛΟΥ ΜΕΤΑ ... Ν ΒΑΣΙ....
The other gives the date †ϚΤΛ† (822), which belonged to the sole reign of the former emperor. These repairs were probably made when Thomas, the rival of Michael for the throne, attacked the fortifications in this quarter. It was precisely in the year 822 that the rebel general encamped beside the Monastery of SS. Cosmas and Damianus (above Eyoub), and then, armed with battering-rams and scaling-ladders, advanced to the assault of the towers of Blachernæ, behind which the standard of Michael floated over the Church of the Theotokos.[[571]]
The tower at the north-western corner of the enclosure was reconstructed by the Emperor Romanus, as an inscription upon it proclaims:
“The Tower of St. Nicholas was restored from the foundations, under Romanus, the Christ-loving Sovereign.”
To which of the four emperors named Romanus the work should be assigned is not easy to decide. The tower must have derived its name from the Church of S. Nicholas in this vicinity, for the site of that church is marked by the Holy Well which still flows amid the graves and trees of the Turkish cemetery within the Brachionion of Blachernæ, an object of veneration alike to Moslems and orthodox Greeks. The grounds on which the opinion rests are that, previous to the erection of the Heraclian Wall, the church is described as without the city bounds, in the district of Blachernæ;[[572]] while after the erection of Leo’s Wall it is spoken of as within the city limits, and close to the gate by which persons proceeded from the Blachernæ quarter to the Cosmidion.[[573]] This is exactly how a building beside the Holy Well between the two walls, and near the Gate of Blachernæ which pierces them, would be described under such circumstances.
The proximity of these walls to the Palace of Blachernæ, as well as their comparative weakness, combined to make them the scene of many historical events.