On September 22, 1927, she married 50-year-old naturalist and explorer William Beebe. Mrs. Theodore Roosevelt was one of the guests at the wedding.
Beebe died in 1962, leaving only half of his estate to his widow. She lived on the couple's farm in Wilmington, Vermont. Her last work, Fighting Quaker: Nathaniel Greene, was published in 1972. When she died, she left her papers to the University of Iowa.
Thane is most famous for her "Williamsburg" series of historical fiction. The books cover several generations of a single family from the American Revolutionary War up to World War II. The action moves from Williamsburg in later books to England, New York City and Richmond, Virginia. The novels are, in chronological order: