Complex sentence: Donald George "Don" Bragg (born May 15,1935) is a retired American athlete who competed mainly in the pole vault and won a gold medal in that event at the 1960 Summer Olympics.
Split into simpler sentences: Donald George "Don" Bragg (born May 15,1935) is a retired American athlete who competed mainly in the pole vault. He won a gold medal in this event at the 1960 Summer Olympics.