Complex sentence: Rulon Gardner (born August 16,1971) is an American Olympian who competed in the 2000 Olympic games, winning the gold medal in Greco-Roman wrestling upon defeating Russian Aleksandr Karelin, who was previously undefeated in 13 years of international competition.
Split into simpler sentences: Rulon Gardner (born August 16,1971) is an American Olympian who competed in the 2000 Olympic games, winning the gold medal in Greco-Roman wrestling. He was named champion after defeating Russian Aleksandr Karelin, who was previously undefeated in 13 years of international competition.