Complex sentence: "Holocauste" had to be euthanized while "Flying Fox" went on to easily win the race and then later that year won the St. Leger Stakes to become the 1899 British Triple Crown Champion.
Split into simpler sentences: Holocauste had to be euthanized while "Flying Fox"went on to win the race. Later that year "Flying Fox" won the St. Leger Stakes to become the 1899 British Triple Crown Champion.