Frank Shamrock (born Frank Alisio Juarez, III; December 8, 1972) is a retired American professional mixed martial artist. Shamrock was the first to hold the UFC Middleweight Championship (later renamed the UFC Light Heavyweight Championship) and retired a four-time defending undefeated champion. Shamrock was the No. 1 ranked pound for pound UFC fighter in the world during his reign as the UFC Middleweight Champion. Shamrock has won numerous titles in other martial arts organizations, including the interim King of Pancrase title, the WEC Light Heavyweight Championship and the Strikeforce Middleweight Championship. Shamrock is widely regarded as one of the greatest mixed martial artists of all time, as well as one of the first complete mixed martial artists, adapting his game from a grounded style of fighting to a more complete, well-rounded, and versatile style that included always improving striking to go along with his skilled ground game.