Christianity, derived from Judaism to become the dominant religion of western Europe and the driving force behind its civilization, has underpinned much of Britain's cultural and artistic heritage for fourteen centuries. There is little evidence of widespread Christianity before the 4th cent., though it was probably introduced earlier by eastern traders along with Mithraism and Isis-worship, popular with the army and fortress-towns: archaeological evidence of a cryptogram has been found at Cirencester (2nd–3rd cents.), chi-rho signs elsewhere, and the first British martyr was Alban. Urban Christianity was sufficiently vibrant to send three bishops (London, York, Colchester) to the Council of Arles (314); the little church at Silchester (c.360), wall-paintings at Lullingstone (Kent), and a Christian mosaic at Hinton St Mary (Dorset) further testify to its vigour. paganism, despite a brief revival 360–80, was in decline as the century ended, when historical figures such as Ninian and Patrick began to emerge and Christianity was becoming the religion not merely of towns and upper classes but of rural estates. On the arrival of Anglo-Saxon invaders with their gods Woden and Thor, British Christianity was virtually extinguished except for the western Celtic fringes relatively untouched by Romanization or Saxon conquest. monasticism (withdrawal from the world) had reached the Celts at a formative stage in their Christianity, and monks rather than bishops led the church. Patrick (c.390–461) evangelized Ireland, Ninian (c.360–c.432) the Picts of Galloway, and Kentigern (d. 612) Strathclyde; Illtud (d. c.540) and David (c.530–c.589) worked in Wales, but had little wish to convert the pagan settlers, though they sent missions to the continent; Columba settled in Iona (c.563), Whence Aidan brought Christianity to Lindisfarne (635). The great legacies of the Celtic church are illuminated manuscripts such as the Books of Kells and Durrow, and the Lindisfarne Gospels. When Roman missionaries under Augustine arrived in Kent (597), divergences between the two strands arising from differences in organization and details such as the date of Easter and style of monkish tonsure led to clashes unresolved until the Synod of Whitby (664), when Roman customs prevailed. Conversion had sometimes been slow, though helped when a ruler embraced the new faith (Æthelbert of Kent, Edwin of Northumbria), but a brief golden age followed statesman- archbishop Theodore's reorganization of scattered dioceses, which produced scholars such as Bede, missionaries like Boniface of Crediton, and growth in the church's status and prestige. Monasteries were not only centres of religion and education but functioned as law-courts, while large investments were made in buildings representing the church (stone replacing wood, built in ‘the Roman style’); secular Anglo-Saxon and Christian cultural traditions began to fuse in both poetry and visual arts (metalwork, manuscripts, carvings). Attacks from Viking raiders during the 9th cent., seen by churchmen as apocalyptic, destroyed religious houses and shifted power and wealth into secular hands, but did not totally destroy the church.

For two centuries after about 1050, when most of western Europe was formally Christian, sustained attempts were made to apply gospel principles and canon law to society generally, through Gregorian reform, clergy discipline, and then modification of lay life. The Norman Conquest, which joined England politically and ecclesiastically with Europe's main states, away from Scandinavia, led to a revival of religious life. Edward the Confessor had already rebuilt the abbey church at Westminster, but ecclesiastical administration was reorganized, cathedrals commenced, and the cathedral school at Oxford grew into a university. Monasticism again flourished, but with changed structure: diverging from the original Benedictines were Cluniacs, Cistercians, and Augustinians, while Hospitallers and Templars were founded for service of Holy Land pilgrims; friars in the west, unlike monks, lived in rather than withdrawn from the world, the Franciscans among the destitute, the Dominicans as teachers, preachers, and scholars. Monasteries were not only repositories of learning but, through the concept of loving one's neighbour, cared for the sick (though the soul remained pre-eminent over the body). A redemptive religion centred on Christ's mediation with God, one of Christianity's attractions in a time of poverty, illness, and the ever-present consideration of early death was its promise of an afterlife with justice or consolation; chantries, schools, and hospitals were frequently founded on earth to buy grace in heaven. Since the prospect of punishment was more dramatic than that of bland paradise—art and literature reveal vividly imaginative interpretations of hell—the threat of eternal damnation was used to enforce a prescription of ethics and attitudes suitable for differing social ranks. High days and holy days punctuated the seasons' calendar, marriage laws for the laity contributed to a form of social welfare, while a knight's fidelity to his lord and protection of the needy was echoed in the adoption of a new position of prayer (kneeling with hands together) resembling feudal homage. At the same time, depictions of Christ in majesty yielded to images of his crucifixion, to encourage devotion. By the 15th cent. explorers, merchants, and colonizers had started to spread Christianity beyond Europe, a process that continued throughout the ensuing centuries. Empire-building not only involved colonization and growth of trade, but active and purposeful extension of religion; the cross followed the flag, sometimes vice versa. Nevertheless, with late 20th-cent. decolonization, Christianity, far from dying in these newly independent territories, became even more vigorous, especially in Africa.

The principal sacraments (or ‘mysteries’) recognized by all Christians, except quakers, are the eucharist and baptism. The eucharist or mass is the central act of most public worship as the re-presentation (sic) of Christ's last supper, death, and resurrection, symbolically feeding the faithful. Baptism is an initiation rite in which the use of water is an outward sign of death to the old self, washing, and fresh life; originally for converted adults, it is now usually administered to infants. Other sacraments, not universally acknowledged, are confirmation, marriage, ordination, confession, and anointing of the sick. Hymn-singing, preaching, reading of Scripture, and prayer form significant parts of worship. The Bible is an important primary written source for most Christians, taken literally by some, but regarded as no more than a history book, with all associated imperfections, by others. The greatest challenges to Christianity have been the doctrinal upheavals that led to the Reformation (and the English church's rupture from Rome) and secularism. The Census Report on Religious Worship (1851–3) caused alarm by its revelation that nearly 40 per cent of the population were unwilling or unable to attend a place of worship. While Christianity remains Britain's established religion at the start of the 21st cent., the challenge from secularism has grown, compounded by disillusion with organized religion, the increasing ethnic mix from immigrants with their own beliefs and practices, and a feeling that spirituality is lacking in a materialistic world. Appeals for improvement in moral values repeatedly call for a return to ‘Christian’ ethics.

Revd Dr William M. Marshall; and Dr A. S. Hargreaves