Stock Photo - Frederick William, the Great Elector, heading the Brandenberg (in present-day Germany) forces, drives back the Swedish invaders under Count Waldemar von Wrangel, near the town of Fehrbellin, at the Battle of Fehrbellin on June 18, 1675. Frederick William was known as the Great Elector following Fehrbellin and especially because of his military and political skills. Electors were members of the electoral college of the Holy Roman Empire and were responsible for Roman king, and then from the mid-1500s forward the Holy Roman Emperor. As a result of William Frederick's victory, his army became the foundation of the later Prussian army. This illustration, a copy of a tapestry, dates to 1910.