Transformation of the Ottoman Empire
Sultan Suleiman I (r. 1520–1566) was the longest-reigning sultan in Ottoman history, but the last years of his reign were characterized by uncertainty over who would be his successor. Suleiman had three sons who could hope to succeed, Mustafa, Bayezid, and Selim. While the latter two were the children of Suleiman's wife Hurrem Sultan, the first was the son of an earlier concubine. Mustafa may have felt that his half-brothers possessed an unfair advantage over him, and thus worked to secure the favor of the military. Perhaps suspecting that Mustafa planned to dethrone him just as his own father had done to his grandfather, Suleiman acted first and in 1553 ordered that Mustafa be executed. The death of Hurrem Sultan in 1558 triggered open conflict between the two remaining candidates, and Selim ultimately emerged victorious. Suleiman further strengthened his son's position by arranging a marriage between Selim's daughter and the influential Sokollu Mehmed Pasha (Grand Vizier 1565–1579). Suleiman died in 1566, while besieging the fortress of Szigetvar in Hungary, bringing Selim to the throne.
Sultan
Western tradition knows the Ottoman ruler as "sultan", but Ottomans themselves used "padişah" (emperor) or "hünkar" to refer to their ruler. The emperor's formal title consisted of "sultan" together with "khan" (for example, Sultan Suleiman Khan). In formal address, the sultan's children were also entitled "sultan", with imperial princes (Şehzade) carrying the title before their given name, with imperial princesses carrying it after. Example, Şehzade Sultan Mehmed and Mihrimah Sultan, son and daughter of Suleiman the Magnificent. Like imperial princesses, living mother and main consort of reigning sultan also carried the title after their given names, for example, Ayşe Hafsa Sultan, Suleiman's mother and first valide sultan, and Hürrem Sultan, Suleiman's chief consort and first haseki sultan. The evolving usage of this title reflected power shifts among imperial women, especially between Sultanate of Women, as the position of main consort eroded over the course of 17th century, the main consort lost the title "sultan", which replaced by "kadin", a title related to the earlier "khatun". Henceforth, the mother of the reigning sultan was the only person of non imperial blood to carry the title "sultan".