The Battle of Rain (also called the Battle of the River Lech or Battle of Lech) was fought on 15 April 1632 as part of the Thirty Years' War. The forces involved in this conflict were 40,000 Swedish troops under Gustavus Adolphus and 25,000 Catholic League troops under Johan Tserclaes, Count of Tilly. It was the second meeting between the two legendary generals (see First Breitenfeld when Tilly received the first setback of his long and storied career) and like at Breitenfeld, Tilly lost when Gustavus forced the river Lech under the cover of his superb artillery.
Gustavus had a bridge of boats constructed across the Lech near the city of Rain through the night prior to the battle, and in the morning sent three hundred FinnishHackapelite troops across the river under fire. The Hackapelites dug earthworks for batteries which then protected the rest of Gustavus' army as they crossed the river. As soon as his army had crossed the river, Gustavus immediately and successfully stormed the hill. Tilly was shot in the leg early in the battle and was moved to the rear; his second in command, Johann von Aldringen, was knocked unconscious with a skull fracture minutes later. Maximilian I, Elector of Bavaria, ordered an immediate retreat to save the now leaderless army, leaving most of the Catholic League's baggage and artillery in the field. The army itself may only have escaped destruction due to a storm and high winds blocking roads in the night that followed.