This is the main entrance to the Hunat Hatun Külliyesi: the usual complex of mosque, medrese and mausoleum. It was founded in 1235-38 by the Seljuk sultan Alaeddin Kaykobad's favorite Mahperi.

The medrese is to the left, in the middle you can see the top of the mausoleum.

Külliye, deriving from the Arabic word "kull" (meaning the whole, all) is a term which designates a complex of buildings, centered around a mosque and managed within a single institution, often based on a vakıf (foundation). Except for the mosque, it can be composed of a medrese (school), a darüşşifa (hospital), kitchens for the poor, bakery, hammam, library, arasta (shops), caravanserai and other buildings for various benevolent services for the community. Often the türbe of the initiator will be present too.

Correspondent: J.M.Criel, Antwerpen.
Source: Wikipedia.