BrandenburgPrussia

Brandenburg-Prussia refers to the German state formed by the personal union of the Margraviate of Brandenburg and the Duchy of Prussia under the House of Hohenzollern. In 1618 Elector John Sigismund of Brandenburg inherited the Prussian duchy, creating a dynastic linkage between Brandenburg and Prussia within the Holy Roman Empire. Although Prussia remained a fief of the Polish crown, the two territories were governed together by the Hohenzollerns as a single realm.

The union was consolidated under Frederick William, the Great Elector (1640–1688), who rebuilt administration after the devastations of the Thirty Years’ War, centralized government, and built a large standing army. His successors expanded Prussian lands and institutionalized governance, laying the groundwork for a unified state and its bureaucratic efficiency.

In 1701, Frederick I, Elector of Brandenburg, was crowned King in Prussia in Königsberg, elevating the realm to the Kingdom of Prussia. The state grew into a major European power, particularly under Frederick William I and Frederick II, who expanded territory and advanced administrative and military reform. Brandenburg-Prussia remained the dominant German power through the 18th and 19th centuries, forming the core of the German Empire established in 1871.

After World War I, the monarchy ended and Prussia became a Free State within the Weimar Republic. The Prussian state was dissolved in 1947 during postwar reorganizations, and Brandenburg reemerged as a distinct federal state in modern Germany. Historians commonly use Brandenburg-Prussia to describe the early modern union that culminated in the Kingdom of Prussia and shaped German statehood.