Karl Heinrich von Nassau-Siegen (French: Charles-Henri-Othon de Nassau-Siegen; 5 January 1743 – 10 April 1808), was a French-born fortune-seeker and adventurer active in Spain, Poland and the Russian Empire.
A controversial figure, he was best known as Catherine II's least successful naval commander.
Charles Henry, in Catherine II's own words, "had everywhere the reputation of a crazy fellow".
He sailed around the world with Bougainville, "fought tigers bare-handed" in Central Africa and reportedly seduced the Queen of Tahiti.
His tiger hunt is the subject of a vast canvas by Francesco Casanova.