The Battle of Als (Danish: Slaget om Als; German: Übergang nach Alsen) was fought on 29 June 1864 during the Second Schleswig War between Denmark and Prussia. It was the last major engagement of the war, as the Prussians under General Herwarth von Bittenfeld secured the island of Als – occupied by 9,000 Danish troops, including the garrison of Dybbøl which had retreated there – in a night attack masterminded by the Chief of Staff (later Field Marshal) Leonhard Graf von Blumenthal.