The Battle of Als (; ) 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. Background On May 12, peace talks began in London. The Danes were offered by the Prussians a border that was close to today's, but it was rejected by the government in Copenhagen. Prussia also proposed a referendum in Schleswig on where the border would go, but it was also rejected. Eventually, the inevitable collapse of the negotiations was due to the defeat at the Battle of Dybbøl on April 18. The Danish negotiators with Prime Minister D.G. Monrad spearheaded the demand for a demarcation at the Eider. On June 26, the ceasefire expired. The allied Prussians and Austrians could continue the war without any problems, so they had to transfer troops from the conquered Jutland to the Danish islands. The Prussian military leadership wanted to attack both Als and Funen at the same time. The Chancellor Otto von Bismarck decided that Als would be conquered first. Prelude Danish plans The Danes had built a network of trenches and artillery positions along the entire coast from Sønderborg in the south to the tip of the Kær Peninsula Arnkilsøre in the north. In the waters around Als, Danish warships and gunboats circled ready to intervene in the event of an attack on the island. While the battle was in progress, the Danish troops would transport the ships anchored up in the 9 km long bay Hørup Hav, east of Sønderborg, but then anchored off the south side of the peninsula Kegnæs, not to be cut off and enclosed by the north-advancing Prussians. The owner of Sandbjerggård, who owned the forest area along Alssund from Sandbjerg to Sottrupskov, had at one point offered the Danish Ministry of War to cut down the parts of the forest facing Alssund, but the Ministry of War did not think the Prussians would use the area. The defense of Als was organized in such a way that the 1st Division got the guarding of the coastline from south of Sønderborg to