Frederick William (1620-1688) was elector of Brandenburg from 1640 to 1688. Known as the Great Elector, he augmented and integrated the Hohenzollern possessions in northern Germany and Prussia.

Born in Berlin on Feb. 16, 1620, Frederick William was the only son of Elector George William and Elizabeth Charlotte of the Palatinate. He was raised in the Reformed faith of the Hohenzollern court and in 1634 went to the University of Leiden, where he dutifully, if unenthusiastically, attended lectures and more happily explored the vital commercial life of the harbor town. His experience in the Netherlands left him with a religious tolerance uncommon in his age and a firm impression of the commercial basis of Dutch power. He returned to Berlin in 1638 only to flee from an invading Swedish army with his ailing father. George William died in Königsberg on Dec. 1, 1640, and Frederick William succeeded him. He was quiet in manner, stocky...