Complex sentence: Henri Chammartin (30 July 1918--30 May 2011) was a Swiss equestrian who won an individual gold medal in dressage at the 1964 Summer Olympics in Tokyo.
Split into simpler sentences: Henri Chammartin (July 30,1918--May 30,2011) was a Swiss equestrian and Olympic champion. He won an individual gold medal in "dressage" at the 1964 Summer Olympics in Tokyo.