Derived from Greek λεων (leon) meaning "lion". This name was borne by a 6th-century BC king of Sparta. During the Christian era it was merged with the Latin cognate Leo, with the result that the two forms are used somewhat interchangeably across European languages. In England during the Middle Ages this was a common name among Jews. A famous bearer was Leon Trotsky (1879-1940), a Russian Communist revolutionary.