Isabella Stewart Gardner (April 14, 1840 – July 17, 1924) was a leading American art collector, philanthropist, and patron of the arts. She founded the Isabella Stewart Gardner Museum in Boston.
Gardner possessed an energetic intellectual curiosity and a love of travel. She was a friend of noted artists and writers of the day, including John Singer Sargent, James McNeill Whistler, Dennis Miller Bunker, Anders Zorn, Henry James, Dodge MacKnight, Okakura Kakuzo and Francis Marion Crawford.
Gardner created much fodder for the gossip columns of the day with her reputation for stylish tastes and unconventional behavior. The Boston society pages called her by many names, including "Belle," "Donna Isabella," "Isabella of Boston," and "Mrs. Jack". Her surprising appearance at a 1912 concert (at what was then a very formal Boston Symphony Orchestra) wearing a white headband emblazoned with "Oh, you Red Sox" was reported at the time to have "almost caused a panic", and still remains in Boston one of the most talked about of her eccentricities.