The Karatay Madrasa, built in 1251, is adjacent to the citadel. Its portal displays alternating stones of light and dark, a hallmark of Syrian influence, and in this case a copy of the portal of the nearby Alaeddin Mosque. The entrance is through a somewhat truncated muqarnas niche, and leads in to a large room with a tiled iwan at one end and surmounted by a tiled dome. The dome is open to the sky; directly below the oculus is a pool for rain that might come in. The transition from the square room to the round dome is accomplished by way of Turkish triangles intracately decorated in black, white, and turquoise tiles. Today the Madrasa serves as a tile museum.
Source:
Rice, Tamara Talbot. The Seljuks in Asia Minor, 280. New York: Praeger, 1961.