 Before the reign of Mehmed II (1444-1446 and 1451-1481), sons of sultans used the title "Çelebi" after their name.The formal way of addressing a şehzade is "Devletlû Najabatlu Şehzade Sultan" (given name) "Hazretleri Efendi", i.e., Sultan Imperial Prince (given name) or simply Imperial Prince (given name).The style of consorts of şehzades is "hanımefendi".