During the Thirty Years' War, Danish troops under King Christian IV occupied the fortified town in 1626. Upon the nearby Battle of Lutter, they were besieged by the Imperial forces of General Gottfried Heinrich Graf zu Pappenheim. Re-conquered in 1627, the Wolfenbüttel fortress remained under the command of Gottfried Huyn von Geleen. In June 1641 the Battle of Wolfenbüttel was fought here, when the Swedish forces under Wrangel and the Count of Königsmark defeated the Austrians under Archduke Leopold of Habsburg, however, they failed to occupy the town.