grand mosque
Ulu Mosque was built by Yıldırım Bayezid between 1396 and 1399. Yıldırım Bayezid wanted to have 20 masjids built in Bursa after the victory of Nicopolis in 1396, but he had the Ulu Mosque built with 20 domes upon the suggestion of his son-in-law Emir Sultan, one of the important scholars of the period. Although the exact architect is not known, some sources mention the name Ali Neccar.

It was the largest example of the multi-domed mosque form in Ottoman architecture. The Grand Mosque is considered the 5th place (after Mecca, Medina, Jerusalem and Damascus) by the scholars of the period among the sacred places in Islam. The Ulu Mosque, which has a rectangular plan, has three doors on the east, west and north facades. The crown gate on the north façade is more magnificent than the others and is made of marble.

The mosque is covered with thick main walls and twenty domes with a diameter of 11 meters, resting on arches and pendentives connecting 12 square-planned masonry elephant legs. The top of the dome in the middle part of the mosque is glazed, and there is a large fountain with 16 corners underneath.

The 129 writings found inside the mosque, some of which belong to famous calligraphers such as Abdülfettah Efendi, Kazasker Mustafa İzzet Efendi, Sami Efendi, Şefik Efendi, are shown as original examples of calligraphy. Examples of the Esmâü'l-Hüsna are written in jali thuluth and kufic calligraphy on each face of the elephant feet. Also in the mosque is Sultan II. There is also a plate belonging to Mahmud.

The pulpit of the mosque, which consists of interlocking pieces in the kundekâri technique, without using nails or any other fasteners, is a work of art and was made by Hacı Muhammed bin Abdulaziz bin İbnü'd-Devâkî. The solar system is depicted on the east side of the pulpit, and the Milky Way galaxy is depicted on the west side. In addition, the inscription on the door of the pulpit states that the mosque was completed in 802 H. (1399) by the order of Yıldırım Bayezid.

At the corners of the northern façade of the mosque, there are minarets with bases made of marble and bodies made of brick.

The mosque was last repaired between 2008-2010.