Answer by taking a quote from the following article:

Man o' War (March 29, 1917 - November 1, 1947) was an American Thoroughbred who is widely considered one of the greatest racehorses of all time. During his career just after World War I, he won 20 of 21 races and $249,465 (equal to $3,047,451 today) in purses. He was the unofficial 1920 American horse of the year and was honored with Babe Ruth as the outstanding athlete of the year by The New York Times. He was inducted into the National Museum of Racing and Hall of Fame in 1957.

Man o' War was a chestnut horse with a white star and stripe on his forehead. He was foaled at Nursery Stud near Lexington, Kentucky. He was bred by August Belmont, Jr., whose father's accomplishments were recognized through the naming of the Belmont Stakes in 1867. Belmont Jr. was an equally notable horseman who served as the chairman of The Jockey Club from 1895 until his death in 1924. Belmont Park was named in the family's honor when it opened in 1905.  Man o' War was sired by Fair Play, a multiple stakes winner who finished second in the 1908 Belmont Stakes to the undefeated Colin. Man o' War was the second foal out of Mahubah, a lightly raced mare by English Triple Crown Champion Rock Sand. Not long after the colt was foaled on March 29, 1917, Belmont Jr. joined the United States Army at age 65 to serve in France during World War I. While he was overseas, his wife named the foal "Man o' War" in honor of her husband. Originally, the Belmonts intended to race Man o' War themselves. However, in the summer of 1918 with the ongoing war effort, they decided to liquidate their racing stable. At the Saratoga yearling sale, Man o' War was sold at a final bid of $5,000 (equivalent to $81,000 in 2017) to Samuel D. Riddle, who brought him to his Glen Riddle Farm near Berlin, Maryland. The underbidder at the auction was Robert L. Gerry, Sr., who is reported to have said to his wife, "Forty-five hundred is enough to spend for any yearling." Two years later in 1920, Riddle declined an offer of $400,000 for the horse.  At maturity, Man o' War stood 16.2 1/2 hands (66.5 inches, 169 cm), with prominent withers and a high croup, but was sometimes faulted for a dipped back that grew more pronounced with age. He had virtually flawless legs and solid bone, traits he passed on to his offspring. He had a slightly Roman nose and notably high head carriage. His nickname was "Big Red", though his coat had tinges of yellow and gold. An energetic, spirited horse, he is often pictured standing very still and gazing off into the distance, described as the "look of eagles". His stride was measured at 28 feet, believed to be the longest of all time.

When was Man o'War born?