In the late 19th and early 20th century, the social status of a woman was often determined by the social status of her husband. As such, the marriage of a wealthy man to a woman from a lower social class could raise the status of the entire family. This was the case for Mary Todd Lincoln, who married Abraham Lincoln in 1842.
The Marvelous Mind of Margaret Cavendish:
An Engaging English Quiz on the Duchess of Newcastle-upon-Tyne