Hagia Irene Museum

Hagia Irene is an ancient Byzantine church located within the outer courtyard of Topkapi Palace in Istanbul's Sultanahmet district. Built during the reign of Emperor Constantine the Great, beginning around 337 CE, its name means "sacred peace." It stands as one of the oldest churches of the Eastern Roman Empire and was historically the second-largest church in Istanbul after Hagia Sophia.

The church holds particular significance because, unlike many other Byzantine religious structures, it was never converted into a mosque following the Ottoman conquest of Constantinople. Instead it served various purposes over the centuries, including as a military arsenal for the Janissaries during Ottoman times. Today it functions as a museum and is notable for its extraordinary acoustics, which have made it a venue for classical music performances.

Much of the church's original ornamentation, including mosaics and frescoes, has been lost to earthquake damage and deterioration over the centuries, so the interior is relatively austere, featuring a large black cross on a golden background within the apse. The building remains an important example of Byzantine architecture and a significant monument to early Christian Constantinople.