Outside the mosque are two mausoleums on a platform. One has a ten-sided roof and was built by Kilij Arslan II. It houses eight sarcophagi of Seljuq sultans of Rum. An other one has eight sides, was unfinished when its founder, Kaykaus I died in 1219). It's constructed from marble. This unfinished mausoleum is known as Adsız Türbe, or the "Anonymous Mausoleum", since the names of those buried within are unknown. Mummified corpses are on view.