The Eagle of the Ninth is a young adult historical adventure novel by English author Rosemary Sutcliff. Set in Roman Britain in the 2nd Century A. D., the narrative follows Marcus Flavius Aquila, a Roman Centurion who dreams of military triumph and is assigned to distant Britain as an Auxiliary Cohort. After being dismissed from the Legion following a tragic injury, Marcus goes on to find new friends, new journeys, and new adventures. Themes explored in The Eagle of the Ninth include connection with nature, loyalty, and the universal need for belonging.