Büyükesence Orhan Mosque

Büyükesence Orhan Mosque, located in the district of Erenler, province of Sakarya, is a mosque built with the log-cabin technique. The mosque is an original early Ottoman architecture example.

The mosque is located in the cemetery of the Büyükesence neighborhood on the road branching north from the 5th km of the Sakarya-Düzce highway. The cemetery is 2 km east of the village center. The mosque served as the Friday Mosque for the villages of Büyükesesence (Büyük Tersiye), Küçükesence (Küçük Tersiye) and Hasanbey. The mosque, used until recent times, is now in a ruined state.

The mosque was built using a technique employed for the first 250 years after the foundation of the Ottoman State. The technique began to be used during the reign of Orhan Gazi and ended during the reign of Suleiman the Magnificent. Because it has side annexes adapted to various needs besides the main prayer area, it is called a Multi‑Space Mosque.

The mosque measures 8.60 × 15.40 m and has a rectangular plan. It rests on a stone foundation on the ground. The ends of the logs, 7–10 cm thick and 20–30 cm wide, are joined by the log‑cabin method with interlocking joints. A thatched plaster was applied over the interior and exterior walls. The mosque has no dome but a roof of the cradle‑cover type. The minaret is not original and was rebuilt after the 1967 earthquake. The mihrab and minbar are not original and were added later.

The mosque has no foundation deed or charter. In the records of the General Directorate of Foundations, it is registered under the name of Orhan Gazi. The exact construction date is unknown; it is estimated to have been built between 1326 and 1359.

In 2023 the mosque was restored by the Bursa Regional Directorate of Foundations and reopened for worship.

Today the mosque is called “Cumaaltı Mosque,” while the newly built mosque next to it is called “Orhan Mosque.”