Wilhelm II's turbulent reign culminated in Germany's guarantee of military support to Austria-Hungary during the crisis of July 1914, one of the direct underlying causes for the World War I. A lax wartime leader, he left virtually all decision-making regarding strategy and organisation of the war effort to the Imperial German Army's Great General Staff. By 29 August 1916, this broad delegation of power resulted in a "de facto" military dictatorship that dominated national policy for the rest of the conflict. Despite emerging victorious over Russia and achieving significant gains in Western Europe, Germany was forced to relinquish all its conquests after its forces' decisive defeat in November 1918. Upon losing the support of the military and his subjects, Wilhelm abdicated his throne and fled to exile in the Netherlands. He remained there during the German occupation in World War II, and died in 1941.