Brewer's: Classic Races
(The). The five chief horse-races in England, viz. the 2,000 and 1,000 guinea races for two-year-olds, run at Newmarket, the Derby for fillies and colts, the Oaks for fillies only, and the St. Leger.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894