The inscriptive plaque (kitabe) above the door to the mosque gives the date of construction -846 A.H. (1442-1443)- and the name of the donor - Mahmud Pasa, a vizier under Murad II who was the son of grand-vizier Çandarli Ibrahim Pasa and the grandson of the prominent Çandarli Halil Hayreddin Pasa. The real or symbolic tomb of Mahmud Pasa is immediately outside the qibla wall, in the cemetery south of the mosque.
Similar in design to the Green Mosque of Iznik, this single-unit sanctuary is composed of a three bay portico and a prayer hall. The portico is enclosed with carved marble balustrades on either side of the entrance that is marked with a rectangular door frame inscribed in the central archway. The bays of the portico are covered with mirror vaults on the sides and a dome at the center. In recent modernization, the space has been englazed for winter use and the wooden door of entry has been replaced with aluminum alternative.
Through a portal niche featuring seats carved into its walls to the east and the west, one reaches the domed space of the prayer hall. Four windows on each wall, with two additional windows in the drum of the dome, illuminate the interior. On the qibla wall, the five-sided mihrab niche is set inside a molded rectangular frame and adorned with a muqarnas ceiling. Little remains of the decorative calligraphy that used to embellish the interior.
The mosque has a single minaret on the northwest corner with stairs beginning at the interior of the mosque inside the northern wall. It is ornamented with rings of red and blue glazed tiles on the shaft and a saw-toothed brick layout on the single balcony (serefe). The construction of the minaret is brick and the walls were built alternating three layers of brick with a single layer of cut-stone.
Sources:
1943. Iznik:Tarih ve Müze Komitesi Yayini. Istanbul: Kenan Matbaasi.
1972. Türkiye'de Vakif Abideler ve Eski Eserler. Volume IV. Ankara: Vakiflar Genel Müdürlügü Yayinlari.
Ayverdi, Ekrem Hakki. 1972. Osmanli mi'marisinde Çelebi ve II. Sultan Murad Devri 806-855 (1403-1451): II. Istanbul: Baha Matbaasi.
Eyice, Semavi. 1988. Iznik: Tarihçesi ve Eski Eserleri (Nicaea: The History and the Monuments). Istanbul: Sanat Tarihi Arastirmalari Dergisi Yayinlari.
Yalman, Bedri. 1999. Iznik (Nicaea). Bursa: Governorship of Bursa, Provincial Directorate of Tourism.