The history of Christianity, which means the study of the history of the Christian religion and the Church, from Jesus and his twelve apostles to the present day. Christianity is a monotheistic religion founded on the teachings and life of Jesus. As for the church, in its theological and Christian sense, it is the institution that Jesus established to continue after him the mission of spreading the culture of salvation among human beings according to Christian beliefs. Christianity began in the first century AD as a small Jewish group, and it quickly spread in the next few centuries throughout the Middle East and the Roman Empire and its settlements in Roman North Africa, including the Church of Carthage, despite the persecutions that the emperors of Rome practiced against the followers of this religion, but since the fourth century It became the religion of the empire and acquired Greek and Roman culture. Armenia was the first country to adopt Christianity as the official religion in 301, followed by Georgia in 319. Ethiopia in 325 and the Roman Empire in 380. During and during the Middle Ages, Christianity continued to spread, reaching northern Europe and Russia. With the advent of the eras of openness and exploration, this religion spread throughout the earth, until it became the largest religion in the world in terms of the number of its followers; Its followers number 2.2 billion, or about a third of the planet's human population.