Thirty Years' War: A Swedish–German army defeated the forces of the Catholic League at the Battle of Rain, mortally wounding their commander Johann Tserclaes, Count of Tilly.

The Thirty Years' War, fought primarily in Central Europe between 1618 and 1648, was one of the most destructive conflicts in European history. An estimated 4.5 to 8 million soldiers and civilians died from battle, famine, or disease, while parts of Germany reported population declines of over 50%. Related conflicts include the Eighty Years' War, the War of the Mantuan Succession, the Franco-Spanish War, the Torstenson War, the Dutch-Portuguese War, and the Portuguese Restoration War.

The Catholic League was a coalition of Catholic states of the Holy Roman Empire formed 10 July 1609. While initially formed as a confederation to act politically to negotiate issues vis-à-vis the Protestant Union, modelled on the more intransigent ultra-Catholic French Catholic League (1576), it was subsequently concluded as a military alliance "for the defence of the Catholic religion and peace within the Empire".

The Battle of Rain took place on 15 April 1632 near Rain in Bavaria during the Thirty Years' War. It was fought by a Swedish army under Gustavus Adolphus of Sweden, and a Catholic League force led by Johann Tserclaes, Count of Tilly. The battle resulted in a Swedish victory, while Tilly was severely wounded and later died of his injuries.

Johann Tserclaes, Count of Tilly was a field marshal who commanded the Catholic League's forces in the Thirty Years' War. From 1620 to 1631, he won an unmatched and demoralizing string of important victories against the Protestants, including White Mountain, Wimpfen, Höchst, Stadtlohn and the Conquest of the Palatinate. He destroyed a Danish army at Lutter and sacked the Protestant city of Magdeburg, which caused the deaths of some 20,000 of the city's inhabitants, both defenders and non-combatants, out of a total population of 25,000.