Abu Ishak Kazeruni Mosque
It was built by Yıldırım Bayezid at the end of the 14th century in the name of Ebu İshak Kazeruni (died in 1035), an Iranian cleric and the founder of the Kazeruniye Order. In the three-line inscription written in thuluth script on the entrance gate, it is written that it was built by Yıldırım Bayezid and repaired during the reign of Fatih Sultan Mehmed.

The walls of the building, which is one of the "⊥" planned mosques (with tabhanes and lodges), are built with rubble stone and bricks are used in between.

The mosque is similar to the Timurtaş Pasha Mosque in plan and consists of the main place of worship covered by a central dome in the middle, tabernacle spaces on both sides, an iwan in the south and the narthex in the north.

The gable wall on the entrance façade was built with three rows of bricks and one row of cut stone, with vertical bricks placed between them. The narthex is a five-sectioned space consisting of pointed arches connecting the side walls and the four pillars in the middle. The octagonal drum dome in the main place of worship is accessed by the Turkish triangle belt. The tabhane spaces located in the east and west directions are entered through a round-arched door. The top of the tabernacle spaces are covered with vaults, the one in the west has a hearth, and the one in the east has a chimney hole.

The minaret with a square base and cylindrical body adjacent to the eastern wall of the narthex was added in 1882. 

Of the complex consisting of a soup kitchen, a school, a private room and a tomb built together with the mosque, only the mosque and the tomb have survived to the present day.   

The Kazeruniye Order, which had many guesthouses in Iran, was protected by Yıldırım Bayezid when it came to Anatolia. It is known that this sect, based on work and cooperation, influenced the Ahi organization in Anatolia.

The mosque was repaired by the Bursa Antiquities Lovers Institution in 1479, 1655, 1760, 1764, 1844, 1882 and finally in 1969.