Christianity

Christianity is the largest world religion by number of followers (around 2.4 billion). Members of the religion are called Christians. Christians generally believe Jesus Christ to be the Son of God, the second person of the Trinity. It is an Abrahamic monotheistic religion, meaning it has only one God. It has its roots in Judaism. It is based on the life and teachings of Jesus.
To most of the people of his time, Jesus was a preacher, teacher, healer, and prophet from ancient Judea. However, his disciples believed him to be much more than that: they believed that Jesus was God's one and only son who was sent down to Earth to die on a cross for their sins. 
The man said to be his father, Joseph, was a carpenter. Jesus was executed by being nailed to a cross (or crucified) under Pontius Pilate, the local Roman governor at the time. His life and followers are written about in the New Testament, part of the Bible. Christians consider the Bible, both the Old Testament and New Testament, as sacred. The Gospels or "The Good News" are the first four books of the New Testament and are about the life of Jesus, his death, and him rising from the dead.
God created the world. Jesus is the name of God the Son. Christians believe Him to be the Son of God. They believe that He was the human son of the Virgin Mary and the divine Son of God. They believe he suffered and died to free humans from their sin and was later raised from the dead. He then went up into Heaven. At the end of time, Jesus will come back to Earth to judge all mankind, both alive and dead, giving everlasting life to those who believe in him. The Holy Spirit is the spirit of God on the Earth that spoke through prophets.
The prophets foretold in the Old Testament of Jesus as the Savior. Christians think of Jesus Christ as a teacher, a role model, and someone who revealed who the Christian God was.
Just like Judaism and Islam, Christianity is an Abrahamic religion. Christianity started out as a Jewish sect in the eastern Mediterranean. It quickly grew in number of believers and influence over a few decades, and by the 4th Century it had become the dominant religion in the Roman Empire. Armenia was the First Nation in the world to adopt Christianity as its official religion, under the rule of King Tiridates III of the Arsacid dynasty in the early 4th century. The Kingdom of Aksum became the first empire to adopt Christianity. During the Middle Ages, the rest of Europe mostly was Christianized. At that time, Christians were mostly a religious minority in the Middle East, North Africa, and parts of India. Following the Age of Discovery, through missionary work and colonization, Christianity spread to Africa, the Americas, and the rest of the world.
Christianity has been an important part of the shaping of the world. As of the early 21st century, Christianity has approximately 2.2 billion followers.
Jesus Christ.
The most basic part of Christianity is the belief in Jesus as the Son of God and Messiah (Christ). The title "Messiah" comes from the Hebrew word ("māšiáħ") meaning "anointed one". The Greek translation "Χριστός" ("Christos") is the source of the English word "Christ". Jesus is English for the Hebrew word Yeshua. 
Christians believe that, as the Messiah, Jesus was anointed by God as ruler and savior of all people. Christians also believe that Jesus' coming was the fulfillment of prophecies of the Old Testament. The Christian belief of the Messiah is much different than the contemporary Jewish concept. The main Christian belief is that, through the death and resurrection of Jesus, sinful humans can be reconciled to God. Through this, they believe they are given salvation and eternal life.
There have been many theological disagreements over the nature of Jesus over the first centuries of Christian history. But Christians generally believe that Jesus is God incarnate and "true God and true man." Jesus, having become fully human, suffered the pain and temptations of a mortal man, but he did not sin. As fully God, he defeated death and came back to life again. According to the Bible, "God raised him from the dead," he ascended to heaven, is "seated at the right hand of the Father" and will return again to fulfill the rest of Messianic prophecy such as the Resurrection of the Dead, the Last Judgment, and the final creation of the Kingdom of God.
The Gospels of Matthew and Luke say that Jesus was conceived by the Holy Spirit and born from the Virgin Mary. Only a little of Jesus' childhood is written in the canonical gospels, but infancy gospels were popular in antiquity. However, the time of Jesus' adulthood the week before his death is written much about in the gospels. Some of the Biblical writings of Jesus' ministry are: his baptism, miracles, preaching, teaching, and deeds.
Death and resurrection of Jesus.
Christians believe the resurrection of Jesus to be the main part of their faith (see 1 Corinthians 15) and the most important event in human history because it would show that Jesus has power over death and has the authority to give people eternal life. 
Among Christian beliefs, the death and resurrection of Jesus are two main events of Christian doctrine and theology. From what the New Testament says, Jesus was crucified, died a physical death, was buried in a tomb, and rose from the dead on the third day afterwards. Most Christians place his death on a Friday each year, which is the first day of his death. Saturday is the second day, and Sunday is the third day. The New Testament writes that after rising from the dead Jesus appeared many times before his Twelve Apostles and disciples. Once He appeared before "more than five hundred brethren at once". This was before Jesus' Ascension to heaven. Jesus' death and resurrection are remembered by Christians in their worship services, and most commonly during Holy Week, which has Good Friday and Easter Sunday in the week.
Salvation of Christ.
Protestantism teaches that eternal salvation is a gift that is given to a person by God's grace. It is sometimes called "unmerited favor." This would mean that Salvation is God bringing humans into a right relationship with God through faith in Jesus Christ. It is the belief that one can be saved (rescued) from sin and the eternal death of hell. Many Protestants believe in the "assurance of salvation"—that God can put confidence in a believer that he has truly received salvation from Jesus Christ.
Catholicism teaches that although in most cases someone must be baptized a Catholic to be saved, it is sometimes possible for people to be saved who have not fully joined the Catholic Church. Catholics normally believe in the importance of "faith working through love" and sacraments in receiving salvation. The Catholic Church teaches that good works and piety, such as obedience to commands, taking the sacraments, going to church, doing penance giving alms, saying prayers, and other things, are important in becoming holy, but strongly emphasize that salvation is through God's grace alone, and all we can do is receive it.
Different denominations and traditions of Christianity believe in forms divine grace. Roman Catholicism and Eastern Orthodoxy teach the complete importance of the free will to work together with grace. Reformed theology teaches the importance of grace by teaching that a person is completely incapable of self-redemption, but the grace of God overcomes even the unwilling heart. Arminianism believes in a synergistic view, while Lutheran and most other Protestant denominations teach justification by grace through faith alone.
Scriptures.
Christianity uses the Bible, a collection of many canonical books in two parts, the Old Testament and the New Testament. It is believed by Christians that they were written by people who were inspired by the Holy Spirit, and therefore it is most often believed to be the word of God. The Bible has been translated into over 600 languages. The translators are able to verify accuracy by using thousands of handwritten copies of the scriptures which are in the original languages of Hebrew Aramaic, and Greek.
Creeds.
Creeds (from Latin "credo" meaning "I believe") are direct doctrinal statements or confessions, usually of religious beliefs. They started as formulas used when someone was baptised. During the Christological controversies of the 4th and 5th centuries they became statements of faith.
Some main Christian creeds are:
Many Christians accept the use of creeds, and often use at least one of the creeds given above. A smaller number of Protestants, notably Restorationists, a movement formed in the wake of the Second Great Awakening in the 19th century of the 19th century United States, oppose the use of creeds.
Trinitarianism.
The Bible mentions God the Father, God the Son, and the Holy Spirit, which are three persons of the one True God. This idea, called Trinity, was developed at the First Council of Nicaea, in 325, and formalized during several church meetings or councils. Today, many Christian groups agree with it. Oriental Orthodox Churches did not agree with the idea, and split after the council. The biggest of the Oriental Orthodox is the Coptic Orthodox Church. The Oriental Orthodox Churches agree with the ideas in the First Council of Nicaea, but they disagree with other councils.
"Trinitarianism" is the teaching that God is three different persons, or has three different relations, within One God; the "Father", the "Son" (Jesus Christ), and the "Holy Spirit". In the words of the Athanasian Creed, "the Father is God, the Son is God, and the Holy Spirit is God, and yet there are not three Gods but one God."
Trinitarianism is the group of Christians who believe in the doctrine of Trinity. Today, most Christian denominations and Churches believe this. Churches have different teachings about the trinitarian formula. Some say the Spirit comes only from the Father. Others say the Spirit comes both from the Father and the Son. This is known as filioque. Nontrinitarianism (also called Oneness) is the beliefs systems that reject the Trinity. Many different Nontrinitarian views, such as adoptionism or modalism, existed in early Christianity, leading to the disputes about Christology.
An example of a more recent Christian movement that rejects trinitarianism is the Church of Jesus Christ of Latter-day Saints. The Latter Day Saints started in the first half of the 19th century, in the United States. There are other smaller Christian groups who also reject trinitarianism.
The afterlife and end times.
Christians believe that human beings will receive judgement from God and are given either eternal life or eternal damnation. This includes the "Last Judgment" as well as the belief of a judgement particular to the soul after death.
There are also some differences among Christians in this belief. For example, in Roman Catholicism, those who die in a state of grace, go into purgatory, where they are cleansed before they can go into heaven.
Christians believe that at the second coming of Christ at the end of time, all who have died will be raised up from the dead for the Last Judgment, when Jesus will establish the Kingdom of God. There is also the belief of Universal Reconciliation. That is the belief that all people will someday be saved, and that hell is not forever. Christians who believe in this view are known as Universalists.
Christians have different ways to talk about the purpose of Jesus' coming: 
Worship.
Worship is thought by most Christians to be a very important part of Christianity all through its history. Many Christian theologians have called humanity "homo adorans", which means "worshiping ," and so the worship of God is at the very center of what it means to be human. This would mean that because God created all humanity, Christians should worship and give praise to God.
Most Christian worship has Scripture reading, talk about Scripture from a leader, singing, prayer together, and a small time for Church work. Christians may meet in special buildings, also called Churches, or outdoors, or at schools, or anywhere Christians feel they are needed.
The main worship service in Catholic Churches is the Mass and the main worship service in many Orthodox Churches is called the Divine Liturgy. In both of these Churches, along with the other parts of worship, the Eucharist or Communion is central. Here a priest by prayer asks God to change a small amount of bread and wine into what Catholics and Orthodox believe is Jesus's real body and blood, but without changing the accidents (appearance, taste, colour, etc.) of the bread and wine. Then the people each may receive a portion. Many Protestant churches have worship services similar to the Mass, some every week, others a few times a year. Some Protestants believe Jesus is really present at the Communion service, and some believe the bread and wine are symbols to help them remember what Jesus did
The Catholic Church has developed a short ceremony, Eucharistic Benediction, worshiping Jesus present in the Eucharist. They also may visit a Church building to pray in the presence of the Eucharist, Eucharistic Adoration.
The Orthodox and Catholic Churches spirituality place importance on the use of human senses such as sight and on the use of beautiful things. Catholic spirituality often involves the use of statues and other artistic representations, candles, incense, and other physical items as reminders or aids to prayer. The Orthodox Churches also use candles, incense, bells, and icons, but not statues. Orthodox and Catholic worship also makes use of movements, such as the Sign of the Cross, made by each person touching first the forehead, then chest, one shoulder, then the other shoulder. There is also bowing, kneeling, and prostration in Catholic and Orthodox worship.
Sacraments.
In Catholic belief and practice, a sacrament is a religious symbol or often a rite which shows divine grace, blessing, or sanctity for the Christian who receives it. Examples of sacraments are Baptism and the Mass." The word is taken from the Latin word "sacramentum", which was used to translate the Greek word for "mystery".
The two most regularly used sacraments are Baptism and Eucharist (communion). Most Catholics use seven Sacraments: Baptism, the ritual immersion of a candidate to welcome them into the church; Confirmation, the sealing of the Covenant; the Eucharist, a ritual where consecrated bread (discs of unleavened, toasted bread) and wine representing Jesus' body and blood are consumed; Holy Orders, Reconciliation of a Penitent (confession), Anointing of the Sick, and Marriage. Some Christian denominations prefer to call them "ordinances". These are the Orders from Christ to all believers found in the New Testament.
Liturgical calendar.
Roman Catholics, Anglicans, Eastern Christians, and traditional Protestant groups center their worship around a liturgical calendar. Some events that are part of this calendar are the "holy days", such as solemnities which honor an event in the life of Jesus or the saints, times of fasting such as Lent, and other events, such as memoria. Christian groups that do not follow a liturgical tradition often keep some celebrations, such as Christmas, Easter,and Pentecost. A few churches do not use a liturgical calendar.
Symbols.
These are some symbols that some denominations or individual churches may use:
History.
Christianity has had a large history from the time of Jesus and his apostles to the present time. Christianity began in the 1st century AD as a Jewish sect but quickly spread throughout the Greco-Roman world. Although it was originally persecuted under the Roman Empire, it later became the state religion. In the Middle Ages it spread into Northern Europe and Russia. During the Age of Exploration, Christianity expanded throughout the world, and is now the largest religion of the world.
The religion had schisms and theological disputes that had as result ten main branches or groupings: Catholicism, Eastern Orthodoxy, the Church of the East (Nestorianism), Oriental Orthodoxy (Miaphysitism), Lutheranism, the Reformed churches (Calvinism), Anglicanism, Anabaptism, Evangelicalism—these last five often grouped and labeled as Protestant—and Nontrinitarianism.
Types of Christianity.
People who call themselves Christians may show or live their faith in different ways. They may also believe different things. Through history, the ten main groups or "denominations" of Christianity have been the (Eastern) Orthodox, the Church of the East (Nestorian), the Oriental Orthodox (Miaphysite), the Catholic, the Anglican, the Lutheran, the Reformed, the Anabaptist, the Evangelical, and the Nontrinitarian churches. These latter six are often grouped together as Protestant, but Nontrinitarians are also more commonly grouped separately. Not all Christians use these titles. Some believe Christianity is bigger and includes others. Some believe Christianity is smaller and does not include all these churches.
Disagreements.
Some of these groups could not agree on certain points about Christian teaching (called “doctrine”) or practice. The first split was in the 5th century after the Church Council of Ephesus. The council agreed Nestorianism was wrong. The Assyrian Church of the East did not agree and split from the rest. The argument was about the nature of Jesus. Should he be regarded as God and human in one combined nature, or in two separate natures? Most of the bishops, following the Pope (the Bishop of Rome), refused to stay in communion with any bishop who would not say "two separate natures". This was also discussed at the Council of Chalcedon, about 20 years later. The Christians who did not agree with the decision of the Council to excommunicate them, became the non-Chalcedonian Orthodox. The largest Non-Chalcedonian Churches are the Coptic Orthodox in Egypt, the Ethiopian Orthodox, the Armenian, and some Lebanese Orthodox Churches. In general, these churches are known as Oriental Orthodox Churches. Recent discussions between the Roman Catholic Pope John Paul II and the Coptic Orthodox Pope Shenouda III concluded that they believe many of the same things after all, even though the Coptic Church does not recognize the Pope of Rome as its leader.
The third split happened in the 11th century. It is called the Great Schism. It was mostly based on the creed being translated incorrectly from Greek into Latin. The disagreements were made worse because the two cultures often did not understand one another. Also, many Crusaders from Western Europe behaved badly. The Christians in Western Europe were led by the Bishop of Rome, known also as the Pope. They are called the Catholic Church. Most Christians in Eastern Europe, Russia, the Middle East and South Asia, and northeast Africa belong to Orthodox, Nestorian, and Miaphysite Christianity, led by the Bishops of other cities or areas.
In the 15th century, the invention of the printing press made it easier for more people to read and study the Bible. This led many thinkers over the years to return to biblical ideas and to break away from the Catholic Church. They started the Protestant Reformation. The most important Protestant leaders were Jan Hus, Martin Luther, and John Calvin. Later some of these groups disagreed amongst themselves so that these denominations split again into smaller groups. The largest Protestant denominations today are within Evangelical, Lutheran, and Reformed Christianity. In England, a similar protest against the Pope, first political and later religious, led to the Church of England which has bishops and officially calls itself Reformed Catholic but is often referred to as Protestant. The Anglican communion of churches includes several churches called "Episcopal" or "Episcopalian" because they have bishops. Some Anglican Churches have a style of worship that is closer to the Protestant services, others worship more like Catholics, but none of them accept the Pope, or are accepted by him. The Anabaptists also arose from disagreements with Lutheran and Reformed Protestants during what is often called the Radical Reformation. The Evangelical churches arose in reaction to what they views as needs for reform within mainstream Protestantism. This can be seen in the rise of non-conformist movements against the Anglican church in Britain and during revivalist movements, prominently in the several Great Awakenings in Britain and North America. Denominations that arose or surged as a result of these Evangelical reform, renewal, and revival movements include Quakers, Baptists, Moravians, Methodists, the Restoration (Stone-Campbell) movement, Adventists, the Holiness movement, Pentecostals, the Fundamentalist movement, the Charismatic movement, Messianic Judaism, among others including many independent and non-denominational churches. In general, some Protestant denominations, especially within Anabaptism and Evangelicalism, differ from the Catholic, Orthodox, Nestorian, and Miaphysite churches in having given up some of the traditional sacraments, having no ordained priesthood, and not having the same fondness for Mary, the mother of Jesus, that the Catholic and Eastern churches have.
Demographics.
With an estimated number of Christians being somewhere around 2.2 billion, split into around 34,000 different denominations, Christianity is the world's largest religion. The Christian share of the world's population has been around 33% for the last hundred years. This has caused Christianity to spread throughout the world, mainly in Europe and North America. It is still the main religion of Europe, the Americas, the Philippines, and Southern Africa. However it is becoming smaller in some areas, some of them are; Oceania (Australia and New Zealand), Northern Europe (with Great Britain, Scandinavia and other places), France, Germany, the Canadian provinces of Ontario, British Columbia, and Quebec, the Western and Northern parts of the United States, and parts of Asia (especially the Middle East, South Korea, Taiwan and Macau).
In most countries in the developed world, the number of people going to church who claim to be Christians has been dropping over the last few decades. Some believe that this is only because many no longer use regular membership in places, for example, churches, while others believe it is because people may be thinking that religion is no longer important.
Ecumenism.
Most churches have for a long time showed that they want to be tolerant with other belief systems, and in the 20th century Christian ecumenism (the uniting of Christians from different backgrounds), advanced in two ways. One way was more cooperation between groups, such as the Edinburgh Missionary Conference of Protestants in 1910, the Justice, Peace and Creation Commission of the World Council of Churches started in 1948 by Protestant and Orthodox churches, and similar national councils, for example the National Council of Churches in Australia with Roman Catholics.
The other way was creating unions for different churches to join together. Congregationalist, Methodist, and Presbyterian churches joined together in 1925 to form the United Church of Canada, and in 1977 to form the Uniting Church in Australia. The Church of South India was formed in 1947 by the union of Anglican, Methodist, Congregationalist, Presbyterian, and Reformed churches. And other such formations have been done by different Christian groups throughout the years.