Which Byzantine monastery complex in Constantinople became Istanbul’s Zeyrek Mosque?

The Byzantine monastery complex that became Istanbul’s Zeyrek Mosque is the Pantokrator Monastery.

Emperor John II Komnenos and his wife, Empress Irene, founded the Pantokrator Monastery in Constantinople during the twelfth century. Its church complex consisted of three connected churches: the central Church of Christ Pantokrator, a church dedicated to the Virgin Eleousa, and a smaller chapel associated with Saint Michael.

The complex served religious, charitable, and imperial functions. The monastery included a hospital, a nursing facility, a home for the elderly, and other institutions reflecting Byzantine ideas about organized Christian charity. It also became an important imperial burial site.

After the Ottoman conquest of Constantinople in 1453, the complex was converted into a mosque and became known as Zeyrek Mosque. The name Pantokrator means “Ruler of All,” a title traditionally applied to Christ. The surviving buildings are among Istanbul’s most important examples of late Byzantine architecture.