The Thirty Years' War left its mark on Eilenburg. The town was initially spared fighting, but it suffered from the catastrophic economic effects of the war. From 1631 the town was directly involved in the war. In 1632 the body of King Gustavus Adolphus of Sweden was laid out in the Red Deer Inn ("Gasthof Roter Hirsch") after he had been killed in the Battle of Lützen (1632). In 1639 Eilenburg was conquered by the troops of Georg von Derfflinger. In 1646 peace negotiations between Saxony and Sweden began in Eilenburg to extend the expiring Armistice of Kötzschenbroda. On 14 September 1648 the Treaty of Eilenburg was signed and meant the end of the Thirty Years' War for Saxony, and as a consequence the town recovered.