Frederick William, Elector of Brandenburg

Frederick William inherited the Electorate of Brandenburg and Duchy of Prussia in 1640, midway through the Thirty Years' War, with his lands fragmented and weak. A committed Calvinist aligned with the rising merchant class, he grasped early that trade mattered as much as bloodlines. His domestic reforms and military investments gave Brandenburg-Prussia structural strength in the new order that emerged after the Peace of Westphalia. The work was patient and shrewd, not flashy—setting the stage for his son to elevate the duchy to a kingdom. He died in 1688, having built the foundation for Prussi…