A chestnut Thoroughbred with a white star and two hind stockings, Aristides was bred by H. Price McGrath and foaled in 1872. He was sired by the great English stud Leamington, which made him a half brother to another great sire, Hall of Famer Longfellow, who, during his racing career, was called "King of the Turf". McGrath did not consider Aristides first rate, though his dam (Sarong) was by one of the United States' greatest sires, Lexington, whose bloodline went back to Glencoe and Hall of Famer Boston.