Church of Sts. Sergius and Bacchus, Istanbul

Begun in 527 by Emperor Justinian, the Church of Saints Sergius and Bacchus in Istanbul was an early experiment in Byzantine architecture, with a large central dome supported by an octagonal base. The church is now a mosque called Küçük Ayasofya Camii (Little Hagia Sophia Mosque), named for its resemblance to the much larger Hagia Sophia built a few years later.


History of the Church of Sts. Sergius and Bacchus

Saints Sergius and Bacchus are Christian Roman soldiers who were martyred in Syria in 303 AD. They became the patron saints of soldiers and their cult was very popular in Syria and beyond.

The Byzantine Emperor Justinian (r. 527-65) was among the saints' devotees. According to legend, when Justinian was a young man he was condemned to death for plotting against Emperor Anastasius. But Sergius and Bacchus appeared to the emperor in a dream, convincing him to release Justinian.

Justinian began construction on a church dedicated to Sergius and Bacchus immediately after becoming emperor himself in 527 AD; it was completed by 536 AD. The architect was Anthemius of Tralles, a mathematician and the author of a book on burning mirrors, the Paradoxographia. The chosen site was just inside the sea walls west of the Hormisdas Palace (where Justinian lived before ascending the throne), next to the Hippodrome.

The church was connected to a three-aisled basilica dedicated to St. Peter and St. Paul, which Justinian had begun to build in 519. None of it survives today. The Church of Sts. Sergius and Bacchus was built on an octagonal floor plan with a central dome, which inspired the design of the great Hagia Sophia, begun just a few years later in 532. The earlier church was therefore dubbed the "Little Ayasofya" (Küçük Ayasofya).

The church was converted into a mosque (camii) in the 16th century under Sultan Beyazit II and remains an active mosque today.

What to See at the Church of Sts. Sergius and Bacchus

The former church is located on the south side of Istanbul next to the Hippodrome; a railway line (near Sirkeci Station) runs between the south wall of the church and sea wall.

The Küçük Ayasofya's interior is decorated and furnished as a mosque, with Arabic calligraphy and designs in blue painted on white walls. Originally, the walls and vault would have been completely covered in golden mosaics, like those that survive from this period in Ravenna, and probably frescoes as well.

The architecture of the building, however, survives fully intact from the Byzantine era. So too does the Greek dedicatory inscription around the central nave:

A fine view of the interior can be had from the gallery - stairs are to the right of the entrance.

Quick Facts on the Church of Sts. Sergius and Bacchus

Site Information
Names:Church of Sts. Sergius and Bacchus · Küçük Aysofya · Sts. Sergius and Bacchus
Categories:churches; mosques; change of religion
Visitor and Contact Information
Coordinates:41.002727° N, 28.972192° E
Address:Istanbul, Turkey
Lodging:View hotels near the Church of Sts. Sergius and Bacchus
Note: This information was accurate when first published and we do our best to keep it updated, but details such as opening hours and prices can change without notice. To avoid disappointment, please check with the site directly before making a special trip.


  1. Constantinople (Istanbul): Church of SS. Sergius and Bacchus -
  2. Jonathan Bardill, "The Church of Sts. Sergius and Bacchus in Constantinople and the Monophysite Refugees." Dumbarton Oaks Papers, Vol. 54 (2000), 1-11.
  3. Frommer's Turkey: From the Blue Mosque to the Blue Lagoon, 3rd ed.
  4. Sergius and Bacchus - Catholic Encyclopedia

More Information

  • John Freely and Ahmet S. Çakmak, Byzantine Monuments of Istanbul.
  • Thomas F. Mathews, The Byzantine Churches of Istanbul: A Photographic Survey (1976), 242-59.
  • Cyril Mango, Studies on Constantinople (1993).
  • Photos of the Church of Sts. Sergius and Bacchus - here on Sacred Destinations
Exterior view of former church from cemetery. © Dick Osseman
View of the dome and minaret. © Dick Osseman
Exterior view (porch added later). © Dick Osseman
Floor plan of the Church of Sergius and Bacchus.
Interior view from gallery. © Dick Osseman
Byzantine capital and Greek inscription. © Dick Osseman
Byzantine capital. © Dick Osseman
Interior of the former church. © Adrian Fletcher

Map of the Church of Sts. Sergius and Bacchus, Istanbul

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