The last emperor of the Ottoman Empire was Mehmed VI, who reigned from 1918 until 1922. His rule occurred during a tumultuous period marked by World War I and the subsequent collapse of the empire. Following the war, the empire faced increasing nationalist movements and foreign invasions. The Sultan's authority diminished, and in 1922, he was formally deposed by Mustafa Kemal Atatürk, resulting in the abolition of the Ottoman Sultanate. This event marked a significant shift in Turkish history, leading to the establishment of the Republic of Turkey and the end of hundreds of years of Ottoman rule.