Complex sentence: After this there is known to have been at least one race in 1750; regular fixtures recommenced in 1759, and were then held every year in August, September or October but from 1772, Whitsuntide became the recognised race-week.
Split into simpler sentences: After this there is known to have been at least one race in 1750; regular fixtures recommenced in 1759, and were then held every year. The race meetings were normally held in August, September or October but from in 1772, Whitsuntide became the recognised race-week.