This historic Denison house, Pequotsepos Manor, was the home for six generations of one American family before it became a museum in 1948. Ann Borodel Denison Gates (affectionately know as "Aunt Annie") established the Denison Society in 1930 for creating an historical museum which tells the story of the Denison family in Mystic, CT. She died in 1941, at which time the house became the property of the Denison Society. World War II was raging at that time so nothing was done until the war was over and the house remained idle.
During the war, the house remained idle and nothing was done to it until the war was over. In 1946, the society hired J. Frederick Kelly, who was a notable Colonial Revival architect, to restore the house as a museum. The society felt that because the house had so much furniture there was little need to look elsewhere for furnishings. However, there was not enough of the Colonial Revival period to make the house solely dedicated to Annie's plan. So the society decided to create the plan that is still in practice where each of the five main rooms represents a different period of history in America and the Denison Family, and therefore features the Denisons who lived in the house at that period.