On the picture: Close-up of the octagonal foot of the northwest minaret; the door is one out of two giving access to the stairs climbing to the minaret’s balcony. (The other door lies inside, in the northwest corner of the prayer hall).
Originally this minaret was the only one erected (around 1399); the second minaret dates from the second decade of the 15th century and was commissioned by sultan Mehmet I Çelebi.

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