1 Thaler - George William Union

George William inherited Brandenburg-Prussia in 1619, just months before the outbreak of the Thirty Years' War placed his territories directly in the path of every major belligerent. He was spectacularly ill-suited for it — indecisive, perpetually broke, and politically paralyzed between the Swedish and Habsburg camps. This thaler was struck in the opening year of his reign, before the war had fully engulfed the region and while the mints could still function with some normalcy.

The "Union" designation refers to the dynastic union of Brandenburg, Prussia, and Cleves-Mark, consolidated under a single ruler following the Jülich-Cleves inheritance crisis of 1609–1614.