Complex sentence: It was in 1904 that the first National Hunt Steeplechase was introduced to the festival, a race which would become known as the Cheltenham Gold Cup in 1924, when it was won by a horse called Red Splash.
Split into simpler sentences: It was in 1904 that the first National Hunt Steeplechase was introduced to the festival. This race became known as the Cheltenham Gold Cup in 1924, when it was won by a horse called Red Splash.