During the 17th century Sweden emerged as a European great power. Before the emergence of the Swedish Empire, Sweden was a very poor, scarcely populated, country on the fringe of European civilization, with no significant power or reputation. Sweden rose to prominence on a continental scale during the tenure of king Gustavus Adolphus, seizing territories from Russia and Poland–Lithuania in multiple conflicts, including the Thirty Years’ War. These military victories made Sweden the continental leader of Protestantism until the Empire’s collapse in 1721. During the Thirty Years’ War, Sweden conquered approximately half of the Holy Roman states. Gustav Adolphus planned to become the new Holy Roman Emperor, ruling over a united Scandinavia and the Holy Roman states, but he died at the Battle of Lützen in 1632.