This mosque was built in 1339, just 13 years after the conquest of the city by the Orhan, son of Osman who captured Bursa and made it the first Ottoman capital. The mosque has been repeatedly restored. It has a T-form ground plan.

On the picture: The south area of the congregation hall, with the ‘mihrab’ and the ‘minber’.
They are examples of late-Ottoman style, mixing 16th century classic design with 19th century Turkish ‘Baroque’, influenced by European Neo-Classicism. The same can be said about the painted decorations on the walls and the dome, which are called ‘kalem işi’ (= work of the pen/paintbrush), because they are inspired on the geometric or stylised ornamentations used by Ottoman calligraphers to illuminate books. These murals are a recent restoration too.

Mihrab = a semicircular niche in the wall of a mosque that indicates the direction of the Kaaba in Mecca and hence the direction that Muslims should face when praying. The wall in which a mihrab appears is the "qibla wall."
Minber = a pulpit in the mosque where the imam (prayer leader) stands to deliver sermons

Correspondent: J.M.Criel, Antwerpen.
Source: (amongst others) Wikipedia.