The two large domes of the prayer hall, covering the mihrab area (on the lower part of the picture) and the central space (on the upper part). Their decoration has been executed in a 16th-17th century Classic Ottoman style.
This kind of design is an example of the Islamic passion for relating areas and objects of disparate size and purpose through their decoration. These patterns could be applied to rugs or books just as well as to ceilings. Hence the name of the technique: ‘kalem işi’ (= work of the pen/paintbrush), being inspired on the geometric or stylised ornamentation used by Ottoman calligraphers to illuminate books.

Correspondent: J.M.Criel, Antwerpen.
Sources: ‘Vakıf Abideler ve eski Eserler (volume III)’ - Vakıflar Genel Müdürlüğü, Ankara 1983
& ‘Islamic Architecture: Ottoman Turkey’ (Godfrey Goodwin) – London 1977 .