Sulayman I (sōōlāmän´, sülī–) or Sulayman the Magnificent, 1494–1566, Ottoman sultan (1520–66), son and successor of Selim I. He is known as Sulayman II when considered as a successor of King Solomon of the Bible and Qur'an. Under him the Ottoman Empire (Turkey) reached the height of its power and prestige. He continued his father's conquests in the Balkans and the Mediterranean, conquering Belgrade in 1521, expelling the Knights Hospitalers from Rhodes in 1522, and inflicting a crushing defeat on the Hungarians at Mohács in 1526. He unsuccessfully besieged Vienna in 1529 and supported John Zapolya (John I of Hungary) against Ferdinand of Hungary and Bohemia (later Holy Roman Emperor Ferdinand I). John's death in 1540 and the accession of John II were pretexts for the outright annexation of Hungary (except for Transylvania and the section held by Ferdinand) to the Ottoman Empire. In 1536, Sulayman entered a formal alliance with Francis I of France against the house of Hapsburg; this alliance remained the basis of Turkish foreign policy for more than three centuries.

Although Sulayman's vassal Barbarossa made the Turkish fleet the terror of the Mediterranean, Sulayman was, on the whole, unsuccessful in his naval warfare against Holy Roman Emperor Charles V and against Venice. He lost Tunis to Charles in 1535 and failed to take Malta in 1565. Sulayman undertook several successful campaigns against Persia. An Ottoman naval expedition to the Red Sea resulted in the conquest of the Arabian coastlands.

Sulayman died during the siege of Szigetvár, having resumed warfare in Hungary in 1566. The later years of Sulayman's reign had been marred by family disputes over the succession. His favorite wife, Roxelana (or Khurema) intrigued against his eldest son, Mustafa, on behalf of her two sons, Selim and Beyazid. Mustafa built up his own faction, which seemed a threat to Sulayman. In 1553, Sulayman had him executed. Upon Roxelana's death, Selim and Beyazid quarreled. Beyazid rose in revolt, met defeat, and fled to Persia. The shah of Persia was induced to return him for a large sum, and Beyazid was executed. Selim succeeded Sulayman as Selim II.

Sulayman's grand viziers, notably Ibrahim (who held office from 1523 until he was executed in 1536), Rustem, and Sokolli, were capable administrators and contributed to the greatness of his reign. In his government Sulayman was distinguished for his justice. His military, educational, and legal reforms earned him the name Sulayman the Lawgiver among Muslims. He was fond of pomp and splendor and was a lavish patron of the arts and of literature. Sinan, the great Turkish architect, worked under his orders (see also Islamic art and architecture).

See biography by H. Lamb (1951); studies by A. H. Lybyer (1913, repr. 1966) and R. B. Merriman (1966).