Why naming it Derby?

The story says a one-and-a-half mile race specially for 3-year-old fillies was first organised in Derbyshire in 1779 at the suggestion of Edward Smith Stanley, the 12th Earl of Derbyshire and Charles Bunbury, a senior steward of the British Jockey Club. The race was named 'Oaks' after the country retreat of Lord Derby. Coincidentally, the first Oaks was won by Lord Derby's horse Bridget.

Since the first Oaks was a great success, Lord Derby and Charles Bunbury planned to organise a mixed race for 3-year-old colts and fillies over a mile in 1780. They tossed a coin to decide the name of the race. As Lord Derby won the toss, this 3-year-old race was named 'Derby'. Coincidentally, the first Derby winner was Diomed owned by Charles Bunbury.