The ‘Şadgeldi Paşa Türbesi’ (dated c. 1382) has the form of an iwan. This kind of tomb is very rare in Turkey. It was built during the Beylik (= Turcoman principality) of Kutluşahlar, or during very early Ottoman rule.

On the picture: Inside the tomb, where five stone cenotaph sarcophagi are still in place.
A cenotaph is an "empty tomb" or a monument erected in honour of a person or group of people whose remains are elsewhere. It can also be the initial tomb for a person who has since been interred elsewhere. The word derives from the Greek: κενοτάφιον = kenotaphion (kenos, one meaning being "empty", and taphos, "tomb"). In general, a Turkish türbe has two rooms: an upper room where the cenotaph sarcophagus/sarcophagi were placed to be visited by relatives and followers, and a room beneath where the remains of the deceased were buried.

Correspondent: J.M.Criel, Antwerpen.
Source: ‘Vakıf Abideler ve eski Eserler’ - Vakıflar Genel Müdürlüğü, Ankara 1983
& Website of ‘kurumsal.kulturturizm.gov.tr’