The Citadel of Blachernae and Its Towers

The Brachionion of Blachernae

The stronghold created by the Walls of Heraclius and Leo was known in Byzantine times as the Brachionion of Blachernae. After the Turkish conquest of Constantinople in 1453, the fortress was renamed the Pentapyrgion, meaning “Fortress of Five Towers.” This name followed the same pattern as the Heptapyrgion, or Castle of the Seven Towers (Yedi Kule), which stood at the southern end of the land walls. Both names reflected the number of towers that guarded each citadel.

Inscriptions and Repairs

Near the southern section of the wall, parts of the structure show signs of repair work, where two important inscriptions can still be seen. One inscription honors the emperors Michael II (820–829) and his son Theophilus (829–842), reading:

“In honor of Michael and Theophilus, the great emperors.”

The second inscription bears the date 822, which falls during the sole reign of Michael II. These repairs likely took place during the rebellion of Thomas the Slav, a powerful general who challenged Michael’s rule Private Tours Bulgaria Varna.

The Rebellion of Thomas the Slav

In the year 822, Thomas laid siege to Constantinople. He camped near the Monastery of Saints Cosmas and Damianus, located above present-day Eyüp. Equipped with battering rams and scaling ladders, his forces attempted to storm the towers of Blachernae. Behind those towers, the imperial standard of Michael II flew proudly over the Church of the Theotokos (Mother of God). Despite the rebel’s efforts, the defenses held, and the Blachernae fortifications proved vital in protecting the city.

The Tower of Romanus

At the northwestern corner of the citadel, a tower was rebuilt by an emperor named Romanus, as confirmed by an inscription declaring:

“Romanus, the Christ-loving Sovereign.”

Historians cannot say for certain which of the four Byzantine emperors named Romanus carried out this work, but the reconstruction demonstrated the continuing importance of the fortress in safeguarding Constantinople’s vulnerable northern side.

The Church of Saint Nicholas and the Holy Well

The tower in this area was closely linked to the Church of Saint Nicholas, which once stood nearby. Today, its site is remembered by the Holy Well (Hagiasma), still flowing within the Turkish cemetery inside the old citadel. This sacred spring has remained a place of veneration for both Muslims and Orthodox Christians throughout the centuries.

Historical records suggest that before the Wall of Heraclius was built, the Church of Saint Nicholas stood outside the city walls in the district of Blachernae. However, after Leo’s Wall was constructed, the church came to be described as within the city limits, near the Gate of Blachernae. This description fits perfectly with the location of the Holy Well, lying between the two defensive walls.

Legacy of the Blachernae Citadel

The citadel of Blachernae, reinforced by multiple emperors and guarded by its towers, played an essential role in the protection of Constantinople. Its walls witnessed rebellions, repairs, and reconstructions, while its holy sites—like the Church of the Theotokos and the Holy Well—remained centers of religious devotion. Even after the fall of the Byzantine Empire, the site continued to hold deep cultural and spiritual meaning for the communities that lived around it.