The present Tomb of Osman Gazi (1258-1326) was built by Sultan Abdülaziz in 1863. It has an octagonal ground plan, with an interior measuring 10 m in diameter.
The large cenotaph sarcophagus is covered with velvet, embroidered in silver thread; an epitaph of two lines gives (in Ottoman Arabic script) the dates of birth, reign and death of the ruler. It is surrounded by a grid, which is inlaid with mother-of-pearl.
The other smaller sarcophagi belong to Alaeddin Paşa (the other son of Osman I, and thus brother of Sultan Orhan), to Asporça Hatun (second wife of Orhan, and a daughter of the Byzantine Emperor Andronikos III) and 15 other relatives of Osman Gazi.

The building itself is in late-Ottoman classical style, while its interior shows the 19th century style, influenced by European Neo-classicism. The wall paintings have been renewed in the late 1990’s, and are now more plain than the former overloaded ‘Turkish Rococo’ decoration.