Friedrich I of Prussia, Kurfürst of Brandenburg, King of Prussia (Fredrick I, July 11, 1657 -- February 25, 1713), Hohenzollern, was the first king of Prussia, reigning from January 18, 1701, until his death. He died in Berlin.

Born in Königsberg, Friedrich became the Kurfürst (Elector) of Brandenburg, in 1688, upon the death of his father Friedrich Wilhelm I. At the time, Friedrich I was known as Friedrich III. He became "Friedrich I", when he became King.

Friedrich I was never called "king of Prussia". His title was "king in Prussia": most of Friedrich's territories were part of the "Holy Roman Empire of the German Nation". And this association of states had a Habsburg Emperor. For reasons of prestige (similar to Piedmont becoming the Kingdom of Sardinia) Friedrich wished to become a king instead of a mere elector-prince. However, no kingdoms could exist in the Holy Roman Empire (with the notable exception of Bohemia). Friedrich convinced the archduke of Austria (and Holy Roman Emperor) to allow him to become king of Prussia in exchange for an alliance against France. The argument was that Prussia had never belonged to the "Holy Roman Empire of German Nation" and therefore there was nothing stopping the elector-prince of Brandenburg also being King of Prussia (the Emperor himself was also King of Hungary, outside of the Empire). To indicate that Friedrich's royalty was limited to Prussia and did not reduce the rights of the Emperor in Friedrich's German territories, he had to call himself "king in Prussia".

(1697 elector August II of Saxony became King of Poland; 1714 The Hanoverian elector became King George I of Great Britain).

Frierich was married three times: First to Elizabeth Henrietta of Hesse-Kassel, with whom he had one child, Louise Dorothea, b. 1680, who died without issue at age 25; then to Sophia Charlotte of Hanover, with whom he had Frederick William I, born in 1688, who succeeded him. In 1708, he married Sophia Louise of Mecklenburg, who survived him but had no children by him.