The treaty of Lübeck ended a stage of the Thirty Years' War referred to as the Lower Saxon or Emperor's War (), which had begun in 1625. Initial success was with the Danish armies, commanded by Christian IV of Denmark and Ernst von Mansfeld. Then, in 1626, their opponents, a Catholic League army commanded by Johann Tserclaes, Count of Tilly, and an army of Ferdinand II, Holy Roman Emperor, commanded by Albrecht von Wallenstein, turned the tide in the battles of Dessau Bridge and Lutter am Barenberge. Mansfeld moved his army toward Silesia and Hungary, but that campaign failed in 1627, and Mansfeld deserted and later died of plague.