Gevher Nesibe was an early 13th century princess of the Sultanate of Rum, the daughter of Kilij Arslan II and sister of Kaykhusraw I.
According to legend, Gevher Nesibe fell in love with a cavalry officer defending the palace of the Seljuk sultan at Konya. Her brother Kaykhusraw I opposed marriage between his sister and the officer so he sent the young man on a various dangerous assignments and campaigns to ensure his death.
Overcome with grief at her lover's death, Gevher Nesibe Sultan fell ill with tuberculosis. The remorseful Kaykhusraw visited her on her deathbed, asked to be forgiven and offered to fulfill any last request she had. Gevher Nesibe Sultan is reported to have replied: "I am very ill. There is no way for me to recover. None of these doctors can deliver me from my illness. I will eventually pass away. My wish is that you use my property to build a hospital in my honor. In this hospital, sick people should be treated with no charge and at the same time, incurable illnesses researched."
Historical record shows that Kaykhusraw carried out his sister's last request, beginning the hospital in Kayseri in 1204. The buildings were designed and built by an architect named Üstad Ömer. The entryway inscription, a common feature of Islamic architecture that usually records the architect's name, is missing, but the information is preserved in written sources elsewhere.
Today, Gevher Nesibe is also the namesake of a magnificent complex at Kayseri comprising the former hospital, an adjoining medrese devoted primarily to medical studies, and a mosque in Kayseri, Turkey. The complex (külliye in Turkish) that she endowed, is considered one of the preeminent monuments of Seljuk architecture.
The hospital was built between 1204 and 1206, and the medrese, whose construction started immediately after Gevher Nesibe's death in 1206, was finished in 1210.
The complex takes its name from the princess. The medrese within is known under a variety of names: the Gevher Nesibe Medrese; the Çifte Medrese (Twin Medrese); or as the Gıyasiye Medrese, after Ghiyath al-Din Kaykhusraw I, who was responsible for its construction. The tomb within the medrese is said to belong to Gevher Nesibe.