Published in Art, Trade and Culture in the Islamic World and Beyond From the Fatimids to the Mughals - Studies Presented to Doris Behrens-Abouseif Edited by Alison Ohta, Michael Rogers and Rosalind Wade Haddon Series Edited by Melanie Gibson and George Manginis, Gingko Library, London, 2016 An octagonal Kufic inscription with the names of the Prophet, the four righteous caliphs and six of the ṣahāba (Companions of the Prophet) is found on the left side of the mihrab of the Sultan Ahmed Mosque in Istanbul. Its patron, Sultan Ahmed I, belonged to the Khalwati Sufi order and the octagonal form of the inscription closely resembles the octagonal Khalwati rose, a symbol of the order. An identical Kufic octagon is also found in the Mamluk Qartawiyya Madrasa, built by the governor of Tripoli, Amir Qaratay, between 1316 and 1326. There is no apparent evidence linking Amir Qaratay to the Khalwati order but it is well-known that Khalwati shaikhs had close relationships with the Mamluk ruling classes in the fourteenth century. This paper compares these two octagonal Kufic inscriptions found in Tripoli and Istanbul and discusses their significance.