The Roman army was central to the success and expansion of the Roman empire. Not only Romans could join the army; Roman citizenship was required for legionaries but non-citizens could join the auxiliary forces. Joining the auxiliaries required a minimum service of 25 years, after which the soldier and his family would be granted citizenship, which brought many benefits, and a small plot of land.
In the years immediately following the Roman invasion, beyond the legionary fortress at Colchester, a small, 4 acre fort at Gosbecks and a probable Roman military supply base at Fingringhoe, the military presence so far known is small. It is possible that this was due to the good relationship that the local tribe, the Trinovantes, had with Rome. Following the Boudiccan rebellion though, this trust had been seriously disrupted and it seems likely that a more obvious military presence would have been established.
Evidence from Great Chesterford suggests that the Roman fort there dates from after the Boudiccan revolt. Great Chesterford was already a thriving settlement at the time of the invasion, and occupies an important strategic location, controlling the river Cam, Ermine Street and the Icknield Way, leading into East Anglia. There is also evidence for a fort at Chelmsford during this period.
Later fortifications included the walled town at Great Chesterford and the Saxon Shore Fort known as Othona at Bradwell-on-Sea.