Muhammad IV, Ottoman sultan

Muhammad IV or Mehmet IV, 1641–92, Ottoman sultan (1648–87). He was proclaimed sultan of the Ottoman Empire (Turkey) by the corps of Janissaries Janissaries (jăn`ĭsâr'ēz) [Turk.,=recruits], elite corps in the service of the Ottoman Empire (Turkey).
..... Click the link for more information. after the deposition and murder of his father, Sultan Ibrahim. Disorder and corruption continued until the Köprülü Mehmed Köprülü, 1583–1661, became grand vizier of Muhammad IV in 1656. He reorganized the Ottoman fleet, conquered (1658) Transylvania, restored internal order (by executing dissidents), reformed the finances, and built forts along the Don and Dnieper rivers.
..... Click the link for more information. family obtained (1656) the office of grand vizier (chief executive officer) and restored order. However, the empire suffered severe setbacks. Algiers freed itself (1669) from Ottoman suzerainty. In 1683 the Turks, in alliance with the Hungarian Thököly Thököly, Imre (ĭm`rĕ tö`kölyə), 1656–1705, Hungarian rebel, of a noble family of N Hungary.
..... Click the link for more information. , besieged Vienna but were repulsed by King John III of Poland. Turkish weakness being apparent, a Holy League was formed to carry the war into Ottoman territory. After the Turkish defeat (1687) at Mohacs by Charles V of Lorraine, Muhammad was deposed. His brother, Sulayman II, succeeded him.