The Roman Empire constituted a complex amalgamation of cultures, languages, and national identities from across the thousands of square miles encompassing Roman territory. Roman armies themselves were conscripted and drafted from different parts of the empire, as evidenced by the fact that Marcus’s own legion is made up entirely of Gaulish recruits. In The Eagle of the Ninth, concrete examples of the ways in which identities were shaped under such circumstances are illustrated through the characters’ contrasting personalities and preferences. As the Roman presence in Britain has existed for approximately 80 years by the time the events in the novel take place, multiple generations have had to contend with and adapt to the changes associated with not just the Roman Army’s occupation and invasion, but also the establishment of homes and cities in Britain by Roman civilians moving there to set up governments, settle, and conduct business. The reactions of individuals and whether they embrace and integrate or reject and resist Roman influence are unique to each person and their relationships and circumstances, as well as their family histories.

The tribes in Britain were at war with one another for centuries before the Romans arrived, and though not as pronounced as their differences with Rome, differences did exist between them such that allegiances were not always guaranteed in collaborating against Rome.