Derby-day is the former great annual London holiday, on which the horse-race for the stakes instituted by LordDerby in 1780 (Derby Stakes) is run. It always falls on a Wednesday, being the second day of the grand race meeting which takes place in the week after TrinitySunday. Research Derby-day
The Derby Stakes is the most famous horse-race in the world. It is run over 2400 meters on EpsomDowns in England on the last Wednesday in May or the first Wednesday in June by colts and fillies three years old. It was founded in 1780 by and named after Edward Smith Stanley, the 12th Earl of Derby. The races were originally known as the Epsom Races, and were famous in Victorian England as the most popular of the English horse-races, being patronised by all classes of people together. Research Derby Stakes