Spencer won the seat for North Lancashire in the 1857 election. He would serve over fifty years in Parliament. Three times Queen Victoria asked him to form a government and become Prime Minister, and he declined each time. In 1891 he became the 8th Duke of Devonshire upon the death of his father. In 1892, at age fifty-eight, he married Louise von Alten, the widowed Duchess of Manchester. After 81 years without one, Chatsworth again had a duchess. She and Spencer had no children. The current (12th) Duke of Devonshire is descended from Spencer's younger brother, Edward. Spencer lived until 1908. In 1911 a statue of him was erected in Whitehall in front of Horse Guards.

In the story... On a Sunday morning when Chatsworth's garden is closed to the public and the gardeners have the day off, Diana goes for a swim in a remote pond in the 105 acre garden. Spencer, visiting his great-uncle's home, happens to be out for a stroll. He comes upon Diana swimming and becomes infatuated with her. She is already engaged to Alan Sterling, a soldier in the Crimean War whose safe return becomes doubtful. Spencer's interest in Diana has to be circumspect but is instrumental in her later ascendancy in London.