Seymour briefly fought as a volunteer in the Anglo-Persian War and almost immediately afterwards, was at the Relief of Lucknow during the Indian Mutiny. He fought in Italy and Sicily, as a civilian volunteer, joining Giuseppe Garibaldi's Esercito Meridionale as a private in 1860. At an early stage he assumed the rank of Captain on the basis that along with his younger brother Lord Edward Seymour he had co-commanded Volunteer Cavalry in England; both brothers assuming the rank of Captain. He distinguished himself in the Battle of Volturnus in late 1860 and in other campaigns. Garibaldi later confirmed his rank of Captain despite the fact that Seymour was merely a civilian volunteer, and he assumed the name pseudonym "Captain Richard Sarsfield" in commemoration of a hero he had heard about when at Christ Church, Oxford. In late 1860, after Garibaldi had appointed Seymour as a "Military Secretary", he accused a brother officer of embezzling Garibaldi funds, the said brother officer challenged Seymour to a duel that his superior officer forbade him to attend. Seymour felt it necessary to be accompanied at all times by bodyguards and to escape back to Britain - which he did. The scandal induced Seymour to give up any thought of involvement in warfare and he was never again to partake in warfare, choosing to travel extensively throughout Europe and study languages, seldom returning home, much to the resentment of his family. In July 1863 he was summoned to the House of Lords through a writ of acceleration in his father's junior title of Baron Seymour.
Personal life
In 1866 Seymour began a relationship with a 17-year-old maid called Rosina Elizabeth Swan, of Higham, Bury St. Edmunds, Suffolk. He took her with him during his travels, returning to England with her in 1868 to live near Brighton. Seymour and Rosina had two children; a girl Ruth Mary was born whilst the couple were in Tangier and a boy Harold St. Maur born in Brighton. A few months after the birth of his son Seymour died during a botched emergency tracheotomy at his own flat in Dover Street, Mayfair, London. If Seymour had married Rosina, Harold would have now been the heir to his grandfather's dukedom and he spent many years trying to prove that a marriage had taken place. Looking for a possible Dutch witness to the marriage by the name of Ravesteyn, he even published an advertisement in a newspaper in the Netherlands in 1924, offering a reward of £50 for proof of the fact without success. In 1885 the 12th Duke died. He had outlived both of his sons. The 12th Duke's brother became the 13thDuke of Somerset.
