The origins of Christianity lie, historically, in the life and ministry of Jesus, extended through his death,
resurrection
, and
ascension
.
Christianity exists in a vast diversity of different styles and forms of organization, but all are agreed that the figure of Jesus is the disclosure of God and the means of human reconciliation with him.
In the early years, ‘Christianity’ was one interpretation, among many at that time, of what God's covenant with Israel and his purpose in creation should be; but in this interpretation, it was believed that Jesus was the promised
messiah
(Heb.,
ha-Mashiach
= messiah = Gk.,
ho Christos
, hence the name ‘Christianity’, which was first used, according to Acts 2. 26, in
c.
40 CE).
Characteristic Christian doctrines emerged from the demand of the New Testament evidence (and from the experience which brought it into being). Jesus mediated the consequence and effect of God, so that on the one hand it was evidently God who was acting and speaking in and through him, and yet on the other it was clear that Jesus addressed God (e.g. in prayer) as apart from himself, as Father (see
ABBA
): this produced a quest in the early centuries to find ways of speaking of these two natures in one person (
Christology
). At the same time, God was clearly present to the life of Jesus (e.g. at his birth and his baptism, and in the directing of his mission), in the ways traditionally spoken of as the
Holy Spirit
. This led to a further quest to find ways of speaking of the interior nature of God, as being in itself, not an abstract unity, but social and relational (i.e. as
Trinity
).
It was also recognized that what Jesus had done during his life for some particular people, in reconciling them to God when they had become estranged from him and from each other, was, as a consequence of his death, resurrection, and ascension, extended to others, and indeed made universal, at least as an opportunity for those who respond in faith. This led to doctrines of
atonement
.
This extension of the consequence of Christ was made immediately realistic, and thus realizable, through the enacted signs of
baptism
and of the
last supper
(
eucharist
).
During the New Testament period, the nature of Christian community (the Church) changed dramatically: the original metaphor of the Church as the Body of Christ, with all parts being of equal importance under the headship of Christ, was changed into a metaphor derived from the Roman army, with a hierarchical organization and vertical levels of authority of
bishops
,
priests
, and
deacons
: the clericalization of the Church and the subordination of the
laity
have remained characteristic of most parts of Christianity down to the present. After the support of
Constantine
and the recognition of Christianity as the religion of the Empire under Theodosius I (emperor, 379–95), Christianity became the major religion of the Roman world.
Faith and practice were constantly disputed and contested, leading to a series of
Councils
in which attempts were made to achieve unity and conformity. Creeds developed from baptismal formulae (which served as ‘passwords’) to summaries of approved and legitimized faith. But major divisions emerged, some of which (e.g. Monophysites) persist as continuing Churches to the present. Especially serious was the schism between E. and W. Christianity. Despite attempts at repair, the
Orthodox
(i.e. E.) Church (itself comprising several different traditions, disciplines, and practices) remains resistant to the claims of the bishop of Rome (the pope) to teaching and jurisdictional authority. W. Christianity was disrupted by the
Reformation
, with the Reformed Churches dividing further, and repeatedly, on issues of doctrine and practice.
The early involvement of Christianity with the Roman Empire led to the development of a religious life which was deliberately separated from the world. It began with the
desert fathers
and spread across the known world. It eventually found expression in the
monastic
orders, notably that of
St Benedict
, and it gained its evangelical outreach in the
religious orders
of the 13th cent. onward.
Throughout its history, the Christian quest to share the good news (
gospel
) of Christ has produced an emphasis on
mission
, especially in the 19th cent., ‘the century of mission’, culminating in the Edinburgh Conference, 1910. As a result, Christianity is found in all parts of the world, and makes up more than a quarter of the world's population.
Liturgically, Christians follow the life, death, resurrection, and ascension of Jesus throughout each year, marking particular days as
festivals
, and celebrating also those who have been exemplary in faith and practice (
saints
). The practices of
prayer
(in its many forms) and worship are fundamental in Christian life.
Vital also is the fact that Christian life should be the manifestation of a pervasive quality of love (
agape
). From this has arisen the recent view that
orthopraxy
is at least as important as orthodoxy (perhaps more so): see
LIBERATION THEOLOGY
. It is this stress on the transformation of human life into love which has led through the centuries to the founding of schools and hospitals, and to the care of the poor, and to the recognition of such people as
Francis of Assisi
as exemplary.