elector of Brandenburg (from 1619) through much of the Thirty Years' War.

Though a Calvinist, George William was persuaded by his Roman Catholic adviser Adam von Schwarzenberg to stay out of the struggle between the Holy Roman emperor and the German Protestant princes. His neutrality won him the hostility of both sides. In 1631 Gustavus II Adolphus (Gustav II Adolf) of Sweden occupied Brandenburg, forcing the elector to join the Protestants, but, after the Swedish defeat by an imperial army at Nördlingen (1634), George William withdrew from the conflict.