Leben. Friedrich III. war der dritte Sohn von Christian IV. von Dänemark und Norwegen (1577–1648) und dessen erster Gemahlin Anna Katharina von Brandenburg, der ältesten Tochter des Kurfürsten Joachim Friedrich von Brandenburg (1546–1608) aus dessen erster Ehe mit Katharina (1549–1602), Tochter des Markgrafen Johann von Brandenburg-Küstrin (1513–1571).
Frederick William was a military commander of wide renown, and his standing army would later become the model for the Prussian Army.He is notable for his joint victory with Swedish forces at the Battle of Warsaw, which, according to Hajo Holborn, marked "the beginning of Prussian military history", but the Swedes turned on him at the behest of King Louis XIV and invaded Brandenburg.
Ulrika Eleonora was the daughter of King Frederick III of Denmark-Norway and his spouse, Queen Sophie Amalie of Brunswick-Lüneburg.She was given a strict upbringing under the supervision of her mother: she was taught several different languages, and was reportedly a good student in drawing and painting.