An important Roman and Byzantine centre, it was the capital of the Empire of Trebizond from 1204 to 1461. Trabzon was subsequently made part of the Ottoman Empire by Mehmet the Conqueror. After the region was conquered in 1461, the Fatih Medrese (1462), Hatuniye Medrese (1515), İskender Pasha Medrese (1529) and Hamza Pasha Medrese (1543) were established as important medreses (educational centers; some of them within külliye complexes) of the period. It was initially a "sanjak" before gaining the status of "eyalet", and finally became a "vilayet" in 1868.