Stoudios Monastery was the fifth-century Byzantine monastery later known as Imrahor Mosque.
The monastery was founded in Constantinople in 462 by the Roman consul Stoudios and dedicated to Saint John the Baptist. Its monastic community became especially influential through strict observance, theological scholarship, manuscript copying, and the defense of icons during the Iconoclast controversies.
The monastery’s church, dedicated to Saint John the Baptist, was a large three-aisled basilica. It was one of the most important monasteries in Constantinople, although much of the complex has disappeared and the surviving church is heavily ruined. The monastery also helped shape later Byzantine monastic practice.
After the Ottoman conquest, the church was converted into the Imrahor Mosque. Earthquakes and fires caused further damage, so the visible remains should not be mistaken for a fully preserved Byzantine basilica.