Complex sentence: In 1934, she and her brother, William duPont, Jr., founded the Montpelier Steeplechase Hunt Races, which are held at the Montpelier horse racing steeplechase course the first Saturday in November each year.
Split into simpler sentences: In 1934, she and her brother, William duPont, Jr., founded the Montpelier Steeplechase Hunt Races. They are held at the Montpelier horse racing steeplechase course the first Saturday in November each year.