After the fall of the Byzantine state in 1453, the Ottoman Turkish conqueror Sultan Mehmed II declared himself to have replaced the Byzantine (Eastern Roman) ruler as the new Kayser-i Rum, literally "Caesar of the Romans". In the Ottoman Millet system, the conquered natives of Turkey and the Balkans were now categorized as the "Rum Millet" (Millet-i Rum) for taxation purposes and were allowed to continue practicing Orthodox Christianity, the religion promulgated by the former Byzantine state. In modern Turkey "Rum" is still used to denote the Orthodox Christian native minority of Turkey, together with its pre-conquest remnant institutions, cf. Rum Ortodoks Patrikhanesi, the Turkish designation of the Istanbul-based Ecumenical Patriarchate of Constantinople, the figurehead for all of Orthodox Christianity.