Christianity is a monotheistic religion based on the life and teachings of Jesus of Nazareth as presented in the New Testament.
The four primary divisions of Christianity are Roman Catholicism, the Orthodox Church, Anglicanism, and Protestantism. There are other Christian groups that do not fit neatly into one of these primary categories. There is a diversity of doctrines and practices among groups calling themselves Christian. These groups are sometimes classified under denominations, though for theological reasons many groups reject this classification system.
The Catholic Church comprises those particular churches, headed by bishops, in communion with the Pope, the Bishop of Rome, as its highest authority in matters of faith, morality and Church governance. Catholics maintain the "one, holy, catholic and apostolic church”, but also acknowledge other Christian churches and communities and work towards reconciliation among all Christians. With more than 1.1 billion baptizedmembers, the Catholic Church is the largest church representing over half of all Christians and one sixth of the world's population.
Like the Roman Catholic Church, the Eastern Orthodox Church also traces its heritage to the foundation of Christianity. A number of conflicts with Western Christianity over questions of doctrine and authority culminated in the Great Schism.
Eastern Orthodoxy is the second largest single denomination in Christianity, with over 200 million adherents.
The Russian Orthodox Church (ROC) is often said to be the largest of the Eastern Orthodox churches in the world and second only to the Roman Catholic Church among Christian churches, numbering over 135 million members world wide and growing numerically since late 1980s. According to the data made public December 12, 2008, the Church had 157 dioceses including 29,263 parishes served by 203 bishops, 27,216 priests and 3,454 deacons.
Estimates of the total number of Protestants are very uncertain, partly because of the difficulty in determining which denominations should be placed in these categories, but it seems clear that Protestantism is the second largest major group of Christians after Catholicism in number of followers (although the Orthodox Church is larger than any single Protestant denomination).
A special grouping are the Anglican churches descended from the Church of England and organised in the Anglican Communion. Some Anglican churches consider themselves both Protestant and Catholic.
All Christians believe Jesus is the son of God, God having become man and the savior of humanity. Christians, therefore, commonly refer to Jesus as Christ or Messiah.
The foundation of Christian theology is expressed in the early Christian ecumenical creeds, which contain claims predominantly accepted by followers of the Christian faith.These professions state that Jesus suffered, died from crucifixion, was buried, and resurrected from the dead to open heaven to those who believe in him and trust him for the remission of their sins (salvation). They further maintain that Jesus bodily ascended into heaven where he rules and reins with God the Father.
Christianity regards the Bible, a collection of canonical books in two parts (the Old Testament and the New Testament), as the authoritative word of God. The New Testament mentions several resurrection appearances of Jesus on different occasions to his twelve apostlesanddisciples, before Jesus' Ascension to heaven. Jesus' death and resurrection are commemorated by Christians in all worship services, with special emphasis during Holy Week which includes Good Fridayand Easter Sunday
Most denominations teach that Jesus will return to judge all humans, living and dead, and grant eternal life to his followers. He is considered the model of a virtuous life and physical incarnation of God. Christians call the message of Jesus Christ the Gospel ("good news") and hence refer to the earliest written accounts of his ministry as gospels.
According to the Gospels of Matthew and Luke, Jesus was conceived by the Holy Spiritand born from the Virgin Mary. Little of Jesus' childhood is recorded in the canonical Gospels while his adulthood, especially the week before his death, are well documented in the Gospels contained within the New Testament.
Christian churches, denominations, and sects are divided regarding the number and operation of the sacraments. Sacraments are generally held to have been instituted by Jesus Christand representa rite, that mediates grace of God. They are usually administered by the clergy to a recipient or recipients. Administering the rite priests use such things as water, oil, and bread and wine, which are blessedorconsecrated.
The two most widely accepted sacraments are Baptism and the Eucharist, however, the majority of Christians recognize seven Sacraments or Divine Mysteries: Baptism, Confirmation (Chrismation in the Orthodox tradition), and the Eucharist, Holy Orders, Reconciliation of a Penitent (confession), Anointing of the Sick, and Matrimony.
As of the early 21st century, Christianity has between 1.5 billion and 2.2 billion adherents.Christianity represents about a quarter to a third of the world's population and is the world's largest religion. In addition, Christianity is the state religion of several countries.