He was born July 4, 1881, in the Glen Riddle section of Delaware County. His father, Samuel, made a fortune as owner of a wool mill and left much of his fortune to his children after his death. The younger Samuel had developed an interest in horses, and in 1918 he spent $5,000 to purchase a colt from railroad tycoon August Belmont. That colt, Man 0' War, who was nicknamed "Big Red," was named the Horse of the Century by the National Museum of Racing and Hall of Fame in Saratoga, New York. Man 0' War raced only in 1919 and 1920, starting 21 times and winning 20. His only loss came in the Sanford Memorial Stakes at Saratoga Aug. 13, 1919. The horse that beat him was named Upset. As a three-year-old, Man 0' War won all 11 of his races, including the Preakness and Belmont Stakes. He was not entered in the Kentucky Derby. His last race was a match race against Kentucky Derby winner Sir Barton, which he won by seven lengths. At Riddle's breeding farm, Man 0' War sired more than 300 colts and fillies who won more than 1,200 races. Included among them was War Admiral, the fourth horse to win the Triple Crown. Riddle, who died at the age of 89, left most of his fortune to establish Riddle Memorial Hospital. In 1999, he was named Delaware County's Horse Racing Figure of the Millennium by the Delaware County Daily Times.