How did Frederick William’s work help prepare the way for the Kingdom of Prussia?

Frederick William, known as the Great Elector, laid the essential foundations for the future Kingdom of Prussia through several key initiatives:

• Sovereignty over Prussia: Through skillful diplomacy and military intervention during the Swedish-Polish War, Frederick William secured full sovereignty over the Duchy of Prussia. The Treaty of Wehlau (1657) and the Peace of Oliva (1660) ended Polish suzerainty, transforming his status from a vassal to a sovereign ruler in that territory.123
• Standing Army: He established a permanent military force to protect his scattered domains. This army became the core of the 18th-century Prussian military machine.2
• Centralized Administration: Frederick William broke the power of the provincial estates by wresting control of taxation and finances from them. By creating a system of fixed taxes and an officialdom dependent solely on the sovereign, he established the groundwork for the powerful bureaucracy that characterized later Prussian absolutism.12

These actions unified his disparate territories under a centralized authority, creating the political and military strength necessary for his son to eventually claim the royal title in 1701.12