 In 1890, Ruth Livingston Mills, the great-grand daughter of Morgan Lewis and the mother of Ogden L. Mills, Secretary of the Treasury, inherited the estate.Not long afterwards, Ruth Livingston Mills and her husband, the financier and philanthropist Ogden Mills, commissioned a remodeling and enlargement of the mansion to the architectural firm of McKim, Mead, and White; the principal architect was Stanford White.Work started in 1895 and when completed in the following year, he had turned the house into a Beaux-Arts mansion with 65 rooms, 14 bathrooms, and 23 fireplaces.