Frederick Henry Louis, was a Prince of Prussia and the younger brother of Frederick the Great, was King of Prussia from 1740 until which year, the longest reign of any Hohenzollern king?
Prince Henry of Prussia (1726–1802) Frederick Henry Louis (German: "Friedrich Heinrich Ludwig" ) (18 January 1726 – 3 August 1802), commonly known as Henry ("Heinrich "), was a Prince of Prussia and the younger brother of Frederick the Great. He also served as a general and statesman, leading Prussian armies in the Silesian Wars and the Seven Years' War, having never lost a battle in the latter. In 1786, he was suggested as a candidate for a monarch for the United States.
Maximilian I, Prince of Hohenzollern-Sigmaringen Maximilian I, Prince of Hohenzollern-Sigmaringen (20 January 1636 – 13 August 1689 in Sigmaringen) was a German nobleman. He was the third ruling Prince of Hohenzollern-Sigmaringen; he ruled from 1681 until his death.