Sambo, a martial art and combat sport developed in Russia in the early 1920s, merged various forms of combat styles such as wrestling, judo and striking into one unique martial art. The popularity of professional wrestling, which was contested under various catch wrestling rules at the time, waned after World War I, when the sport split into two genres: "shoot", in which the fighters actually competed, and "show", which evolved into modern professional wrestling. In 1936, heavyweight boxing contender Kingfish Levinsky and professional wrestler Ray Steele competed in a mixed match, which catch wrestler Steele won in 35 seconds.