High Quality Content by WIKIPEDIA articles! The Diana Stakes is an American Thoroughbred horse race. Named for the mythological goddess Diana, the race is run each year at Saratoga Race Course in Saratoga Springs, New York. Inaugurated in 1939, it is open to fillies and mares age three and up willing to race the one and one-eighth miles on the turf. The race is a Grade I with a purse of $500,000.