Christian Cyrus Leben (born July 21, 1980) is an American former mixed martial artist, referee, and bare knuckle boxer. A professional MMA competitor from 2002 until 2013, he most notably competed in the UFC in the Middleweight division, compiling a record of 12–10 in 22 appearances for the organization. Leben first appeared in the inaugural season of The Ultimate Fighter reality series, and also fought in the now-defunct WEC. He began his UFC career with five victories in a row before suffering a knockout loss to future UFC Middleweight Champion Anderson Silva, and was known for his toughness and powerful left hand. Leben was the inaugural WEC Middleweight Champion.