The conflict was sparked by the revolt of the Protestant nobility of Bohemia against emperor Matthias' succession policies. After imperial triumph at the Battle of White Mountain and a short-lived peace, the war grew to become a political European conflict by the intervention of King Christian IV of Denmark from 1625 to 1630, Gustavus Adolphus of Sweden from 1630 to 1648 and France under Cardinal Richelieu from 1635 to 1648. The conflict increasingly evolved into a struggle between the French House of Bourbon and the House of Habsburg for predominance in Europe, for which the central German territories of the empire served as the battleground.