Inside the tomb of Prince Ahmet, a son of father Beyazit II and mother Bülbül Hatun. It is built on an octagonal plan, situated between the Muradiye Mosque and the tomb of Murat II. A notice indicated It was erected by Yavuz Sultan Selim in 1513 (who had him killed). In the Wikipedia I read that it was his mother who erected the tomb (and was buried there herself later).

On the picture: A close-up of the upper part of the mihrab (prayer niche) inside the mausoleum of Şehzade Mahmut, a son of Bayezit II. The mihrab and its tiles are original (1506); the calligraphic murals are later work.

Correspondent: J.M.Criel, Antwerpen.
Source: ‘Vakıf Abideler ve eski Eserler III’ - Vakıflar Genel Müdürlüğü, Ankara 1983 .