Germany, or more exactly the old Holy Roman Empire, in the 18th century entered a period of decline that would finally lead to the dissolution of the Empire during the Napoleonic Wars. Since the Peace of Westphalia in 1648, the Empire had been fragmented into numerous independent states (Kleinstaaterei).

During the Thirty Years' War, various armies repeatedly marched across the disconnected Hohenzollern lands, especially the occupying Swedes. Frederick William I, reformed the army to defend the lands and starts to consolidate power. Frederick William I acquires East Pomerania via the Peace of Westphalia.

Frederick William I reorganized his loose and scattered territories and managed to throw off the vassalage of Prussia under the Kingdom of Poland during the Second Northern War. He received the Duchy of Prussia as a fief from the Swedish king who later granted him full sovereignty in the Treaty of Labiau (November 1656). In 1657 the Polish king renewed this grant in the treaties of Wehlau and Bromberg. With Prussia, the Brandenburg Hohenzollern dynasty now held a territory free of any feudal obligations, which constituted the basis for their later elevation to kings. In order to address the demographic problem of Prussia's largely rural population of about three million, he attracted the immigration and settlement of French Huguenots in urban areas. Many became craftsmen and entrepreneurs.

In the War of the Spanish Succession, in return for an alliance against France, the Great Elector's son, Frederick III, was allowed to elevate Prussia to a kingdom in the Crown Treaty of 16 November 1700. Frederick crowned himself "King in Prussia" as Frederick I on 18 January 1701. Legally, no kingdoms could exist in the Holy Roman Empire except for Bohemia. However, Frederick took the line that since Prussia had never been part of the empire and the Hohenzollerns were fully sovereign over it, he could elevate Prussia to a kingdom.