American Flag, who won the 1925 Belmont Stakes, is from one of the most successful sirelines in that classic’s history. But it was through his daughters, not his sons, that American Flag left his legacy to the breed. A century after his Belmont victory, he is linked to this year’s Kentucky Derby winner, Sovereignty, as well as a number of other prospects for the 2025 Belmont Stakes. The sireline’s success in the Belmont Stakes began with 1879 winner Spendthrift, who sired the wickedly tempered Hastings, victor of the 1896 edition. Hastings went on to sire 1902 Belmont winner Masterman and nearly had another winner in 1908 when Fair Play was second by a head to unbeaten Colin, in what the official chart dubbed “a wonderfully game race.” Fair Play went on to sire three Belmont Stakes winners, two of whom would sire Belmont winners themselves. Leading off his trio was the great Man o’ War, who won the 1920 edition and went on to sire three Belmont winners: American Flag in 1925, Crusader in 1926, and Triple Crown winner War Admiral in 1937. Man o’ War was followed by 1924 Belmont winner Mad Play and 1927 winner Chance Shot, who sired 1934 winner Peace Chance. :: DRF's Belmont Stakes Headquarters: Contenders, latest news, and more It would be nearly a century before another stallion sired as many Belmont Stakes winners, as Tapit has emerged as the king of the race’s modern history, with Tonalist (2014), Creator (2016), Tapwrit (2017), and Essential Quality (2021). Tapit is tied with Lexington, America’s leading sire 16 times despite his stud career at Woodburn Farm being interrupted by the Civil War, for the all-time Belmont sire record with those four winners. Lexington’s quartet consisted of General Duke (1868), Kingfisher (1870), Harry Bassett (1871), and Duke of Magenta (1878). Fair Play and Man o’ War are among three other stallions to sire three Belmont winners. They are joined by Lexington’s contemporary Australian, shipped to safe harbor in Illinois during the Civil War. He sired Joe Daniels (1872), Springbok (1873), and the aforementioned Spendthrift. American Flag, from Man o’ War’s first crop of 12 named foals, was out of the unraced Irish-bred mare Lady Comfey. She was imported to the U.S. by Walter Jeffords, nephew of Man o’ War’s owner Samuel Riddle, to support the champion at stud. The Roi Herode mare was a half-sister to Irish Oaks winner Snow Maiden and English St Leger winner Caligula. Breeding the mare to Man o’ War produced a high-headed chestnut colt, who reportedly bore an uncanny resemblance to his sire. American Flag won eight of 17 career starts. A stakes winner at 2, he was unbeaten through a number of major events at age 3 and was named the retrospective divisional champion of that year. Chief among those wins was the 1925 Belmont Stakes, then contested at 1 3/8 miles. American Flag won by eight lengths “in a canter,” per the chart comments. American Flag returned to the races at 4 and was second to the younger Crusader in the Suburban Handicap. According to statistics from The Jockey Club, American Flag – who stood alongside his sire at Faraway Farm and likely got the second tier of his owner’s mares due to this coexistence – sired 183 named foals over his career, with 109 winners. The best-known of his 16 stakes winners was Nellie Flag, who was out of Nellie Morse, the 1924 Preakness Stakes winner. Calumet Farm purchased Nellie Morse while she was carrying Nellie Flag, and the resulting filly became the first homebred champion for the historic operation, winning multiple stakes at age 2 to earn divisional honors. Nellie Flag went on to become a foundational mare for Calumet, producing champion Mar-Kell, 1943 Kentucky Oaks winner Nellie L., and stakes winner Sunshine Nell. More significantly, seven of Nellie Flag’s daughters produced stakes winners. Nellie L., a Blenheim mare foaled in 1940, was among those, and her influence continues. More than 80 years later, she appears in Sovereignty’s direct female line. Nellie L.’s unraced daughter Comely Nell is best known for producing 1976 Kentucky Derby winner Bold Forbes. Comely Nell’s stakes-producing daughter Priceless Fame, a full sister to Bold Forbes, in turn produced the winning mare Milliardaire, who then produced multiple Grade 1 winner Lakeway. Lakeaway’s stakes-winning daughter Sluice produced Grade 1 winner Mushka, who is the dam of the Bernardini mare Crowned, whose son Sovereignty reigned in this year’s Derby. Along with Nellie Flag’s influences in modern families, American Flag has another major tie to modern racing through another of his daughters, Lady Glory. She produced Raise You, who, when bred to Native Dancer, produced Raise a Native. Although his racing career was cut short by injury, he became a major influence at stud, siring Mr. Prospector, Alydar, Exclusive Native, and other successful sons. Mr. Prospector’s branch of the line has continued to flourish through the likes of his sons Smart Strike and Gone West and his grandson Unbridled, among others. Direct male-line descendants of Raise a Native who are potential candidates for this Belmont include Preakness winner Journalism, by Smart Strike’s son, Curlin; Hill Road, by Gone West’s grandson, Quality Road; and Baeza, a great-great-great grandson of Mr. Prospector. :: Want to learn more about handicapping and wagering? Check out DRF's Handicapping 101 and Wagering 101 pages.