Sheikh Izzeddin was a 14th-century Sufi sheikh and teacher in Ankara whose students were largely within the Ahi organization; an Ottoman waqf document calls him a seyyid. His death date is disputed: the inscription is read either as 705/1306 or 752/1352. His tomb in Ulus/Haci Bayram is a reconstruction built on the foundations of the original demolished in the 1930s. (Sources: Kultur Envanteri, 'Seyh Izzettin Tomb/Mosque'; Konyali, History of Ankara.)