This is the inside view of a Türbe or grave monument for Emir Ali.

The Emir Ali Türbesi was built in 1351, during the rule of the Beylik of Eretna. It has the usual structure of a Seljuk tomb, with a prayer room under a (in this case: very flat) pyramidal roof, with a cellar/burial chamber beneath.

The ‘Eretnaoğulları’ was an Anatolian beylik (principality) that succeeded the Ilkhanid governors in Anatolia and that ruled in a large region extending between Kayseri, Sivas and Amasya between 1328–1381. Although short-lived, the Beylik of Eretna left important works of architecture.
The dynasty's founder, Alaeddin Eretna, was a Mongol officer of Uyghur origin in the service of Timurtaş, the Ilkhanid governor of Anatolia. After his master unsuccessfully revolted in 1327, The Persian Ilkhan Abu Said appointed Eretna a governor of Anatolia. When the Ilkhanid rule collapsed in 1335, Eretna was able to establish his own beylik with the title of Sultan under the protection of the Mamluk Sultanate (Egypt). After Eretna's death (1352), his lands were nibbled away by the Ottomans in the west and Akkoyunlu in the east due to internal disputes between the Eretnids. The Beylik's last ruler, Muhammad II, was replaced by his vizier Kadı Burhaneddin who reigned in the same region for another eighteen years.

Correspondent: J.M.Criel, Antwerpen.
Sources: ‘Kayseri Kültür Varlıkları Envanteri’ (Kayseri Belediyesi 2008) & Wikipedia .