The 1,700-year-old grave was reportedly discovered while restoration teams were working at the Şeyh Süleyman Mosque.
The grave was found at the ground floor of the mosque and was confirmed by Italian experts and officials from the Directorate General of Foundations.
The restoration was part of a project including archaeological excavations, seismological tests and scans near the mosque’s site and also unveiled various graffiti from the Ottoman period.
Archaeologist Murat Sav told the HaberTürk daily that the grave was constructed in the late Roman era.
“There are two more floors under the mosque from the Roman era,” Sav said, adding that the underground floor consists of an eight-section burial chamber, referred to as arcosolium.
He noted that in one of the sections they discovered a piece of altar used to offer sacrifices, which was looted during the Byzantine period.
Sav also said that they found Byzantine-era amphorae at the roof of the mosque and have put them under protection.
The Şeyh Süleyman Mosque was converted from a former Byzantine building which was part of the Eastern Orthodox Pantokrator Monastery. Its usage during the Byzantine era is unclear. According to some scholars it could have been a burial place, while others think that it was the library of the monastery. The small octagonal building is a minor example of architecture of the Byzantine middle period in Constantinople.