Altlandsberg was first mentioned in a 1230 deed, it was located at the site of a former Slavic (Sprevane) settlement. The area then was resettled in the course of the German Ostsiedlung, promoted both by the Ascanian Margraves of Brandenburg and the rivaling Margraves of Meissen from the House of Wettin. The town's name may refer to Saxon Landsberg Castle and therefore indicate an establishment by the Wettins. In 1245 the tensions rose to an armed conflict, in which the Ascanians maintained their grounds. From that time on Altlandsberg remained with Brandenburg.
The city was laid out at the behest of the Ascanian rulers, their successor Margrave Louis I from the Bavarian House of Wittelsbach even established a monastery of the Servite Order in 1335, which was dissolved during the Protestant Reformation. Altlandsberg was devastated by the Hussites in 1432, it was affected by several town fires and plague epidemics in the 16th century. The medieval town burnt down completely in 1632 during the Thirty Years' War. A hoard of 7450 gold and silver coins dating from the 14th and early 15th century was discovered in the grounds of the former manor in late 2016. The dates suggest that it was buried in order to protect it during the Hussite wars. It is the largest hitherto found in the state of Brandenburg, and is now being examined in the archeological museum in Brandenburg an der Havel.
Development of Population since 1875 within the Current Boundaries (Blue Line: Population; Dotted Line: Comparison to Population Development of Brandenburg state; Grey Background: Time of Nazi rule; Red Background: Time of Communist rule)
Recent Population Development (Blue Line) and Forecasts
Population development within the current boundaries (2013)