The Battle of Colberger Heide was a naval battle of the Torstenson War which was fought between Sweden and Denmark in 1644.
Despite being Protestant and starting the Thirty Years' War on the same side, Denmark and Sweden were natural rivals. Sweden's successes made King Christian IV of Denmark increase the tax on trade passing through the straits. When word leaked out that the Danes were negotiating an alliance with the Habsburgs, this made war inevitable. Chancellor Axel Oxtenstierna had Marshal Gustav Horn attack from the north, Admiral Klas Fleming secure the Baltic Sea, and Lennart Torstenson assault Jutland from the south. Tortenson invaded Holstein and captured a number of forces, enabling the Swedes to invade Jutland in January 1644. Leaving some troops to besiege Gluckstadt, Torstenson moved the rest to the narrow channel separating the mainland from the isle of Funen, while Horn captured Halland and Scania, apart from Malmo. Both generals needed Fleming to win the naval battle to take the Danish capital of Copenhagen. However, King Christian IV took command of the Danish fleets and defeated the Swedes in a number of naval battles between February and July, most important among them the Battle of Colberger Heide, after which Fleming was killed and the Swedish fleet blockaded in Kiel.