Complex sentence: Mark John Dean (born October 13,1967) is an American former competition swimmer who won the gold medal in the men's 200-meter butterfly event at the 1991 Pan American Games in Havana, Cuba.
Split into simpler sentences: Mark John Dean (born October 13,1967) is an American former competition swimmer. He later won the gold medal in the men's 200-meter butterfly event at the 1991 Pan American Games in Havana, Cuba.