She rode one and led the other to the winner's circle.
In seven decades of showing just about every kind of horse, from high- jumping hunters to powerful Percherons, Mrs. du Pont had many moments of triumph.
There was the time, she recalled during a 1979 interview, when she won a hunt team class at a horse show in Washington in 1921. Her trophy was handed over by Gen. John J. "Black Jack" Pershing.
In all, she took home more than 32,000 ribbons and trophies - awards that covered the walls of an entire room in her pillared Newtown Square mansion on her 600-acre estate, Liseter Hall Farm.
"We've always done our share of winning," Mrs. du Pont once allowed to a reporter, with a twinkle in her eye.
Her equestrian interests were nurtured early in life. Mrs. du Pont grew up around horses in Rosemont and earned her first blue ribbon in 1910 - for the first pony she showed.
In 1919, she married a horseman - William du Pont Jr., who built the Delaware Park race track, designed steeplechase courses, raised racehorses and served as master of Foxcatcher Hounds.
For their marriage, Mrs. du Pont's father gave them Liseter Hall Farm, and her husband's father, a grandson of E.I. du Pont de Nemours, founder of the giant chemical and plastics company, gave them a replica of James Madison's house.
In the 1920s and 1930s, the couple traveled to so many shows together - 19 one summer, always tranporting the horses by train - that Mrs. du Pont once reflected with a laugh, "I felt as though I belonged to a circus."
The du Ponts divorced in 1940, but Mrs. du Pont remained at the farm. And it was there, also in 1940, that her interest in Welsh ponies took off.
Over the years she bred, raised and sold more than 600, including numerous champions. Her Liseter Welsh ponies, as she named them, achieved such distinction that they have almost become a breed unto themselves.
"She raised some of the best Welsh ponies in the world there on that farm," said Richard McDevitt, president of the Devon Horse Show for 18 years and former president of the American Horse Shows Association. "She was a great sportsperson and was the leader of the Welsh pony breeders, for as long as I've known her, in the United States."
Mrs. du Pont became president of the Welsh Ponies Society of America, and for the last 28 years organized the Welsh Pony Show.
She was often consulted in equestrian circles for her advice, and in 1981 she was the the first person inducted into the American Horse Shows Association Hall of Fame.
Along with her show activities, Mrs. du Pont was remembered for often having her children or grandchildren along at the Devon Horse Show. In the show's carriage marathon, Mrs. du Pont could be seen driving her matched ponies with carriage seats full of family members in tow.
"You could always count on her being there with her children and grandchildren," McDevitt said. ". . . She was a delightful person, outgoing, full of energy. She had a good sense of humor."
It was in that spirit that she wanted to be remembered, her family said.
Mrs. du Pont also was a Red Cross volunteer during World War II.
Survivors include two daughters, Jean Ellen Shehan and Evelyn Donaldson; two sons, Henry E.I. and John Eleuthere; 12 grandchildren, and 18 great- grandchildren.
Memorial services will be at 10 a.m. tomorrow at Liseter Hall Farm, Newtown Square. Entombment will be private.