State organisation of the Ottoman Empire
The Ottoman Empire was an absolute monarchy during much of its existence. By the second half of the fifteenth century, the sultan sat at the apex of a hierarchical system and acted in political, military, judicial, social, and religious capacities under a variety of titles.[a] He was theoretically responsible only to God and God's law (the Islamic شریعت şeriat, known in Arabic as شريعة sharia), of which he was the chief executor. His heavenly mandate was reflected in Islamic titles such as "shadow of God on Earth" (ظل الله في العالم ẓıll Allāh fī'l-ʿalem) and "caliph of the face of the earth" (خلیفه روی زمین Ḫalife-i rū-yi zemīn). All offices were filled by his authority, and every law was issued by him in the form of a decree called firman (فرمان). He was the supreme military commander and had the official title to all land. Osman (died 1323/4) son of Ertuğrul was the first ruler of the Ottoman state, which during his reign constituted a small principality (beylik) in the region of Bithynia on the frontier of the Byzantine Empire.
After the conquest of Constantinople in 1453 by Mehmed II, Ottoman sultans came to regard themselves as the successors of the Roman Empire, hence their occasional use of the titles Caesar (قیصر Qayser) of Rûm, and emperor, as well as the caliph of Islam.[b] Newly enthroned Ottoman rulers were girded with the Sword of Osman, an important ceremony that served as the equivalent of European monarchs' coronation. A non-girded sultan was not eligible to have his children included in the line of succession.
Although absolute in theory and in principle, the sultan's powers were limited in practice. Political decisions had to take into account the opinions and attitudes of important members of the dynasty, the bureaucratic and military establishments, as well as religious leaders. Beginning in the last decades of the sixteenth century, the role of the Ottoman sultans in the government of the empire began to decrease, in a period known as the Transformation of the Ottoman Empire. Despite being barred from inheriting the throne, women of the Imperial Harem—especially the reigning sultan's mother, known as the Valide Sultan—also played an important behind-the-scenes political role, effectively ruling the empire during the period known as the Sultanate of Women.
Constitutionalism was only established during the reign Abdul Hamid II, who thus became the empire's last absolute ruler and its reluctant first constitutional monarch. Although Abdul Hamid II abolished the parliament and the constitution to return to personal rule in 1878, he was again forced in 1908 to reinstall constitutionalism and was deposed. Since 2017, the head of the House of Osman and pretender to the defunct Ottoman throne has been Dündar Ali Osman, a great-grandson of Abdulhamid II.