Little Hagia Sophia (Küçük Ayasofya): the Church of Saints Sergius and Bacchus

Updated on October 4, 2026

A ten-minute walk downhill from the Blue Mosque, in the Kadırga district, Little Hagia Sophia (Küçük Ayasofya Camii) is the former Church of Saints Sergius and Bacchus, built around 527-536 under Emperor Justinian and his wife Theodora, a few years before Hagia Sophia. Around 1500, under Sultan Bayezid II, Hüseyin Ağa, chief eunuch of the palace, had it converted into a mosque and added a portico, a minaret, a mihrab and a madrasa. Damaged by earthquakes, then by the construction of the railway in the 19th century, it underwent a full restoration completed in 2006-2007. Today it is a working mosque that can be visited free of charge outside prayer times. Allow 20 to 30 minutes.

Highlights

The ribbed dome

The plan is an octagon set inside an irregular quadrilateral, covered by an "umbrella" dome with sixteen segments, pierced with windows and adorned with calligraphic medallions. Stand in the middle of the hall to take in the whole dome.

Justinian's Greek frieze

Below the gallery runs a marble frieze carved with a Greek inscription in relief, celebrating Justinian, Theodora and Saint Sergius. It recalls the building's dedication, long before its conversion into a mosque. Look up at the entablature above the ground-floor columns.

The columns and the gallery

On three sides, a two-storey colonnade alternates green and red marble columns, topped by carved Byzantine capitals. This double colonnade beneath the dome gives an idea of the architecture Justinian would go on to use on a far larger scale at Hagia Sophia.

Around the mosque

From outside, the building keeps its Byzantine walls of brick and stone, beneath the dome set on its octagonal drum. Opposite the entrance, the cells of Hüseyin Ağa's madrasa surround a leafy courtyard with a fountain, which in recent years has housed traditional craft workshops and a tea garden. North of the mosque stand Hüseyin Ağa's octagonal tomb and a small cemetery with Ottoman gravestones.

Infos pratiques

Tips

Entry is free; a donation box helps with upkeep. The mosque closes to visitors during the five daily prayers and on Fridays until the end of the midday prayer. Dress code: shoulders and knees covered, hair covered for women, shoes off at the entrance to the prayer hall. Speak quietly and do not photograph worshippers at prayer. The mosque is far less crowded than the major sights of Sultanahmet: a good stop to understand Byzantine architecture without the crowds. Information as observed in October 2026.

How to get there

Küçük Ayasofya Mahallesi, Küçük Ayasofya Camii Sokak 20, 34122 Fatih, Istanbul. Tram T1, Sultanahmet stop, then about a 10-minute walk: go behind the Blue Mosque through the Arasta Bazaar and head down Küçük Ayasofya Camii street. Sirkeci-Kazlıçeşme suburban rail line, Cankurtaran station, about a 10-minute walk. The mosque stands just north of the railway line that runs along the Sea of Marmara.