Mustafa I, called Mustafa the Saint during his second reign, and called Mustafa the Mad by historians, was twice the sultan of the Ottoman Empire from 22 November 1617 to 26 February 1618, and from 20 May 1622 to 10 September 1623. He was the son of sultan Mehmed III and Halime Sultan.

Mehmed III was the sultan of the Ottoman Empire from 1595 until his death in 1603. Mehmed was known for ordering the execution of his brothers and leading the army in the Long Turkish War, during which the Ottoman army was victorious at the decisive Battle of Keresztes. This victory was however undermined by some military losses such as in Gyor and Nikopol. He also ordered the successful quelling of the Jelali rebellions. The sultan also communicated with the court of Elizabeth I on the grounds of stronger commercial relations and in the hopes of England to ally with the Ottomans against the Spanish.