Kasım Ağa Mosque, Istanbul

The Kasım Ağa Mosque features a square plan with Byzantine brick and stone walls, maintaining a northeast-southwest orientation and single nave design.

Originally constructed as a Byzantine church in the 10th century, the structure was transformed into a mosque by Kasım Bey bin Abdullah in 1506.

The mosque exemplifies the transformation of religious structures in Istanbul, connecting Byzantine architectural heritage with Islamic practices through its design elements.

Located near the ancient Gate of Charisius between Chora Church and Fethiye Mosque, the building serves as an active place of worship.

The mosque underwent multiple construction phases, with surviving walls revealing different building periods and techniques from both Byzantine and Ottoman eras.

Location: Istanbul

Architectural style: Byzantine architecture

GPS coordinates: 41.02900,28.93900

Latest update: March 7, 2025 00:13