Zeyrek Mosque, originally the 12th-century Pantokrator Monastery, stands as one of Istanbul’s most significant yet overlooked landmarks. Built by Empress Eirene and later expanded by Emperor John II Komnenos, the complex once included a hospital, library, and imperial tombs. After the Ottoman conquest, it was respectfully converted into a mosque and madrasa, named after scholar Molla Zeyrek. Despite suffering from plunder, earthquakes, and neglect, recent restorations have revived its historical and architectural splendor. Today, Zeyrek Mosque embodies a unique fusion of Byzantine and Ottoman heritage, offering visitors a quieter, more reflective experience in the heart of old Istanbul.