Much of Great Britain was incorporated into the Roman Empire in 43 AD, after Claudius led the Roman conquest of Britain, conquering lands inhabited by Celtic Britons.
The indigenous religious traditions of the Britons under their priests the Druids were suppressed; most notably Gaius Suetonius Paulinus launched an attack on Ynys Môn in 60 AD and destroyed the shrine and sacred groves there.
In the years following this, Roman influence saw the importation of several religious cults into Britain, including Roman mythology, Mithraism and the imperial cult.
One of these sects, then disapproved by the Roman authorities, was the Levantine-originated religion of Christianity.
While it is unclear exactly how it arrived, the earliest British figures considered saints by the Christians are St. Alban followed by Ss Julius and Aaron, all in the 3rd century.

Eventually, the position of the Roman authorities on Christianity moved from hostility to toleration with the Edict of Milan in 313 AD, and then enforcement as state religion following the Edict of Thessalonica in 380 AD, becoming a key component of Romano-British culture and society.
Records note that Romano-British bishops, such as Restitutus, attended the Council of Arles in 314, which confirmed the theological findings of an earlier convocation held in Rome (the Council of Rome) in 313.
The Roman departure from Britain in the following century and the subsequent Germanic invasions sharply decreased contact between Britain and Continental Europe.
Christianity, however, continued to flourish in the Brittonic areas of Great Britain.
During this period certain practices and traditions took hold in Britain and in Ireland that are collectively known as Celtic Christianity.
Distinct features of Celtic Christianity include a unique monastic tonsure and calculations for the date of Easter.
Regardless of these differences, historians do not consider this Celtic or British Christianity a distinct church separate from general Western European Christianity.
Much of Great Britain was incorporated into the Roman Empire in 43 AD, after Claudius led the Roman conquest of Britain, conquering lands inhabited by Celtic Britons. The indigenous religious traditions of the Britons under their priests the Druids were suppressed; most notably Gaius Suetonius Paulinus launched an attack on Ynys Môn in 60 AD and destroyed the shrine and sacred groves there. In the years following this, Roman influence saw the importation of several religious cults into Britain, including Roman mythology, Mithraism and the imperial cult. One of these sects, then disapproved by the Roman authorities, was the Levantine-originated religion of Christianity. While it is unclear exactly how it arrived, the earliest British figures considered saints by the Christians are St. Alban followed by Ss Julius and Aaron, all in the 3rd century.
Eventually, the position of the Roman authorities on Christianity moved from hostility to toleration with the Edict of Milan in 313 AD, and then enforcement as state religion following the Edict of Thessalonica in 380 AD, becoming a key component of Romano-British culture and society. Records note that Romano-British bishops, such as Restitutus, attended the Council of Arles in 314, which confirmed the theological findings of an earlier convocation held in Rome (the Council of Rome) in 313. The Roman departure from Britain in the following century and the subsequent Germanic invasions sharply decreased contact between Britain and Continental Europe. Christianity, however, continued to flourish in the Brittonic areas of Great Britain. During this period certain practices and traditions took hold in Britain and in Ireland that are collectively known as Celtic Christianity. Distinct features of Celtic Christianity include a unique monastic tonsure and calculations for the date of Easter. Regardless of these differences, historians do not consider this Celtic or British Christianity a distinct church separate from general Western European Christianity.
Catholic Church in England and Wales