Note 060
From Chapter 65 of the Decline & Fall

Since the name of Caesar had been transferred to the sultans of Roum, the Greek princes of Constantinople (Sherefeddin, l. v. c. 54) were confounded with the Christian lords of Gallipoli, Thessalonica, etc. under the title of Tekkur, which is derived by corruption from the genitive Ancient Greek (Cantemir, p. 51).