The Great Northern War (1700–1721) was a conflict in which a coalition led by the Tsardom of Russia successfully contested the supremacy of the Swedish Empire in Central, Northern, and Eastern Europe. The initial leaders of the anti-Swedish alliance were Peter the Great of Russia, Frederick IV of Denmark–Norway and Augustus II the Strong of Saxony-Poland. Frederick IV and Augustus II were forced out of the alliance in 1700 and 1706 respectively, but rejoined it in 1709. George I of Brunswick-Lüneburg (Hanover) joined the coalition in 1714 for Hanover and in 1717 for Britain, and Frederick William I of Brandenburg-Prussia joined it in 1715.