Christianity is one of the world’s largest religions – with over 2.4 billion followers and 33 percent of the global populations proclaiming themselves as Christians. All in all, Christian believe that Jesus is the Son of God and the savior of humanity – and that His coming as the Messiah was prophesied in the Old Testament. Jesus suffered, died, was buried, descended into hell, and rose from the dead, in order for others to trust in Him for the remission of their sins. His incarnation, ministry, crucifixion and resurrection are known as “the gospel”. Which is the term meaning “good news”. The gospel refers to written accounts of Jesus’ life and teachings. Four canonicals, and included in the Bible, are Matthew, Mark, Luke and John.

Throughout history, Christians have debated and through theological disputes about their religion. There are many important distinctions of interpretation and opinion of the Bible and sacred tradition on which the foundation of Christianity is built upon. Since many of these debates have ended in irreconcilable differences in theology and a lack of consensus of the core tenets of Christianity, Catholics, Protestants, Orthodox, and Evangelicals often deny that members of certain branches are in fact true Christians.

The question of how old Christianity actually is can be debated, but the consensus is that it is a little over 2,000 years old. Christianity, like other religions, has adherents whose beliefs and biblical interpretations are different. For Christians, the inspired Word of God is categorized with the biblical canon, the Old Testament, and the New Testament. A traditionalist believes that God worked through human authors so that they produced what God wished to communicate to His current and future followers. Some people believe that divine inspiration categorizes the present Bible as inerrant. However, others claim inerrancy for the Bible in its original manuscripts despite none of those are extant.

Christianity began as a Jewish sect in the Levant of the Middle East around the mid-1st century. Other than Second Temple Judaism, the primary religious influences of early Christianity are Zoroastrianism and Gnosticism. According to the Christian scriptures, Christians were from the beginning subject to persecution by some Jewish and Roman religious authorities who disagreed with the apostles’ teachings. Further widespread persecutions of the Church occurred under nine subsequent Roman emperors. From the year 150, Christian teachers began producing theological and apologetic works aimed towards defending their faith. These authors are known as the Church Fathers, and study of them is called Patristics. Notable early Fathers include Ignatius of Antioch, Polycarp, Justin Martyr, Irenaeus, Tertullian, Clement of Alexandria and Origen. However, Armenia is considered the first nation to accept Christianity in AD 301.

With around 2.4 billion adherents, split into three main branches of Catholic, Protestant and Eastern Orthodox, Christianity is the world's largest religion. The Christian share of the world's population has stood at around 33 percent for the last hundred years, which says that one in three persons on earth are Christians. This masks a major shift in the demographics of Christianity; large increases in the developing world have been accompanied by substantial declines in the developed world, mainly in Europe and North America. According to a 2015 Pew Research Center study, within the next four decades, Christians will remain the world's largest religion; and by 2050, the Christian population is expected to exceed 3 billion.

Christianity has had a significant impact on education as the church created the bases of a number of educational systems. Historically, Christianity has often been a patron of science and medicine. It has been prolific in the foundation of schools, universities and hospitals, and many Catholic clergy - Jesuits in particular, have been active in the sciences throughout history and have made significant contributions to the development of science. Protestantism also has had an important influence on science. According to the Merton Thesis, there was a positive correlation between the rise of English Puritanism and German Pietism on the one hand and early experimental science on the other. The civilizing influence of Christianity includes social welfare, founding hospitals, economics, politics, architecture, literature, personal hygiene, and family life.

Christians have made a numerous amount of contributions to human progress in a broad and diverse range of fields, including philosophy, science and technology, fine arts and architecture, politics, literatures, music, and business. In fact, according to 100 Years of Nobel Prizes a review of Nobel prizes award between 1901 and 2000 reveals that (65.4 percent) of Nobel Prizes Laureates, have identified Christianity in its various forms as their religious preference. Cultural Christians are secular people with a Christian heritage who may not believe in the religious claims of Christianity, but who retain an affinity for the popular culture, art, music and so on related to it. Another frequent application of the term is to distinguish political groups in areas of mixed religious backgrounds.

Criticism of Christianity and Christians dates back to the Apostolic Age, with the New Testament recording friction between the followers of Jesus and the Pharisees and scribes. Examples of this can be seen in Matthew 15:1-20 and Mark 7:1–23. In the 2nd century, Christianity was criticized by the Jews on various grounds. The claims were that the prophecies of the Hebrew Bible could not have been fulfilled by Jesus, given that He did not have a successful life. Additionally a sacrifice to remove sins in advance, for everyone or as a human being, did not fit to the Jewish sacrifice ritual, furthermore God is said to judge people on their deeds instead of their beliefs.

Ultimately, theorists will continue to delve into the proof of Christianity and formulate their own perspective timelines. However, the majority of research and proof from the Bible age Christianity at approximately 2,000 years old – give or take 10 to 20 years. The breakdown of core tenets is incredibly interesting because that is where the timelines begin to venture off into various paths that make it more difficult to track and pinpoint events. Nonetheless, it’s important as Christians to know the general timeline of events that took place from the beginning because these major times have created the Christian lifestyle and upbringing that we live in today.