English: The mosque if that of a son of Sultan Yıldırım Bayezid, Ertuğrul Bey, who was tasked by his father, Sultan Yıldırım Bayezid I, to try and unite all of the Anatolian principalities. Yet he met his death on the battlefield in 1398, losing his young life at the hands of Kadi Burhan Al-Din. Ertuğrul Bey's remains were carried back to Bursa, which was then the first capital of the Ottoman state. The mosque was built with a simple grave in the garden. That has been replaced in a 1954 restoration. The mosque underwent restorations in 1550, 1860, 1892 and 1954, according to text on site. The Ertuğrul Camii has an almost square prayer hall (10 x 10,40 m, under a flat ceiling), which is preceded on the north side by a porch, 10 m wide and 5 m deep. The mosque was founded in the very end of the 14th century, but had to be restored/rebuilt several times; however, unlike many other Bursa buildings, it survived the 1855 earthquake quite well. Its inner decoration is refreshed regularly and displays a plain Classical Ottoman style.