Citadel Spandau is located on the same island of the river Havel where once stood the “castle Spandow”. Documents mention this castle as early as 1229, however, as a foundation of Albert the bear it is likely to be much older.

In 1197, the castle became the domicile of a margravial steward whom the Ascanian margraves Johann I, Margrave of Brandenburg and Otto III, Margrave of Brandenburg were following. Bavarian margraves also resided at the castle Spandow. On 16 December 1352 margrave Louis the Roman, Elector of Brandenburg donated the castle to the council of Spandow. The Julius tower and castle tower, two of Spandau’s most famous sights, were built during the reign of Charles IV, Holy Roman Emperor.

In 1557 Joachim II Hector, Elector of Brandenburg commissioned the reconstruction of the castle into a citadel. The project was assigned to painter and architect Christof Römer in 1560. In 1562 Venetian architect Franciscus Chiramella de Gandino took over the construction of the citadel. In 1572, John George I, Elector of Saxony commissioned Rocco Guerrini with the completion of the project. The construction of the citadel was completed in 1594.

Swedish troops were the first to besiege the citadel in 1631. During the Second Silesian War the citadel was set into defence alert. Since John George I, the citadel was used as a prison for state offenders including including German nationalist Friedrich Ludwig Jahn and the valet of Frederick the Great, who tried to poison the king at Austrian behest and later confessed his crime.

On 25 October 1806 the citadel’s garrison surrendered to the French army under Napoleon. Napoleon visited the citadel on 26 October 1806. It was retaken by Prussian and Russian forces in 1813, but the ramparts were heavily damaged during the battle and required extensive restoration. The Juliusturm continued to be used as a prison; from 1871 until 1919 120 million Mark in gold were stored at the citadel. During the First and Second World War the citadel served military purposes and was closed for the public.