The Great Northern War 1700-1721 was fought between Russia and Sweden for supremacy in the Baltic Sea. Initially, Russia joined the coalition in the war with Denmark and Saxony - composed of the so-called Northern Alliance, but after the outbreak of hostilities the Union collapsed, and was rebuilt in 1709. At various stages of the war other participants attended: on the side of Russia - Hanover, Holland, Prussia, the Polish-Lithuanian Commonwealth; on the side of Sweden – The Ottoman Empire, Zaporozhian Cossacks, and others. The war ended with the defeat of Sweden in 1721, leaving Russia dominant in the Baltic Sea and a major player in European politics. The war began as a coordinated attack on Sweden by the coalition in 1700 and ended in 1721 with the Treaty of Nystad and the Stockholm treaties.