Abdul Hamid I becomes Sultan of the Ottoman Empire and Caliph of Islam.

Abdulhamid I or Abdul Hamid I was the 27th sultan of the Ottoman Empire from 1774 to 1789. A devout and pacifist sultan, he inherited a bankrupt empire and sought military reforms, including overhauling the Janissaries and navy. Despite internal efforts and quelling revolts in Syria, Egypt, and Greece, his reign saw the critical loss of Crimea and defeat by Russia and Austria. The 1774 Treaty of Küçük Kaynarca granted Russia territorial and religious influence. He died soon after the fall of Ochakov in 1788.

The sultans of the Ottoman Empire, who were all members of the Ottoman dynasty, ruled over the transcontinental empire from its perceived inception in 1299 to its dissolution in 1922. At its height, the Ottoman Empire spanned an area from Hungary in the north to Yemen in the south and from Algeria in the west to Iraq in the east. Administered at first from the city of Söğüt since before 1280 and then from the city of Bursa since 1323 or 1324, the empire's capital was moved to Adrianople in 1363 following its conquest by Murad I and then to Constantinople in 1453 following its conquest by Mehmed II.

A caliphate is an institution or public office under the leadership of an Islamic steward with the title of caliph, a person considered a political–religious successor to the Islamic prophet Muhammad and a leader of the entire Muslim world (ummah). Historically, the caliphates were polities based on Islam which developed into multi-ethnic trans-national empires.