This is the Alaca Kümbet.

Due to the latest investigations (2006) historians tend to (re)date this tomb as early as 1184-1190 (Rüm Seljuk period). It has a classical Seljuk appearance, with an octagonal pyramidal roof and a square cenotaph room, but there is no cellar/burial chamber. The only decorated areas are the entrance door and the windows.

On the picture: The tomb seen from the northwest. The building inscription above the western windows states, the ‘Kümbet’ was built for Emir Sadrettin Ömer bin Celaleddin Muhammed.

Correspondent: J.M.Criel, Antwerpen
Source: ‘Tarihi Kayseri Cami ve Mescidleri’ – Doç. Ilhan Özkeçeci (1997)