Johann Tserclaes, Count of Tilly (Dutch: Johan t'Serclaes; February 1559 – 30 April 1632), commanded the Catholic League's forces in the Thirty Years' War. He had a string of important victories against the Protestants but was then defeated by forces led by the King Gustavus Adolphus of Sweden. Along with Duke Albrecht von Wallenstein of Friedland and Mecklenburg, he was one of two chief commanders of the Holy Roman Empire’s forces in the first half of the war.