During much of the 12th century, Dachau was the primary residence of a smaller branch from the House of Wittelsbach led by Otto I, Count of Scheyern-Dauchau. When Conrad III died in 1182, Duke Otto I of Bavaria purchased the land and granted it market rights, that were then affirmed between 1270 and 1280 by Duke Ludwig II der Strenge (the Strict).
As the Allies began to advance on Nazi Germany, the SS began to evacuate the first concentration camps in summer 1944. Thousands of prisoners were killed before the evacuation due to being ill or unable to walk. At the end of 1944, the overcrowding of camps began to take its toll on the prisoners. The unhygienic conditions and the supplies of food rations became disastrous. In November a typhus fever epidemic broke out that took thousands of lives.
After 1945 the name was applied to the displaced persons camp established nearby, but it is most commonly associated with the concentration camp. From 1941 to 1945, almost 20,000 Soviet prisoners of war and a further 50,000 inmates died there. Overcrowding, lack of food and poor sanitary conditions caused outbreaks of typhus, tuberculosis, typhoid fever and dysentery, leading to the deaths of more than 35,000 people in the first few months of 1945, shortly before and after the liberation.