One vector of Roman influence into British life was the grant of Roman citizenship. At first this grant went out very selectively: to the council members of certain classes of towns, which Roman practice made citizens; to veterans, either legionaries or soldiers in auxiliary units; and to a number of natives whose patrons were able to obtain it for them -- some of the local Celtic kingss, such as Togidubnus, received citizenship in this manner. However, the number of citizens steadily increased over the years, as people inherited citizenship and more grants were made. Eventually all people who were not slaves or freed slaves were granted citizenship by the Constitutio Antoniniana in AD 212.
The other inhabitants of Britain, who did not enjoy citizenship, were Peregrini, who continued to live under the laws of their ancestors. The principal handicaps were that they could not:
Christianity came to Britain in the third century. One early figure was Saint Alban, who was martyred near the Roman town of Verulamium, on the site of the modern St Albans, by tradition during the reign of the emperor Decius.
After the withdrawal of Roman troops in the reign of the emperor Honorius the Romano-British were forced to defend their Romanised civilisation with their own forces. The depredations of the Picts forced them to seek help from the pagan Saxons, who were seeking land for their expanding population. However the Saxons eventually turned on their hosts, confining the Romano-British into the western part of the island, notably in Wales and Cornwall.
The struggles of this period gave rise to the legends of Uther Pendragon and King Arthur. It is sometimes said that Ambrosius Aurelianus, the leader of the Romano-British forces, was the model for the former, and that Arthur's court of Camelot is an idealised Welsh memory of pre-Saxon Romano-British civilisation.