The Swedish intervention in the Thirty Years’ War, which took place between 1630 and 1635, was a major turning point of the war, often considered to be an independent conflict. After several attempts by the Holy Roman Empire to prevent the spread of Protestantism in Europe, King Gustav II Adolf of Sweden ordered a full-scale invasion of the Catholic states. Although he was killed in action, his armies successfully defeated their enemies and gave birth to the Swedish Empire after proving their ability in combat. The new European power would last for a hundred years before being overwhelmed by numerous enemies in the Great Northern War.
