From Wikipedia

Peter And Paul
Episode Two

The Empire And The Kingdom

The history of Christianity concerns the Christian religion and the Christian Church, from the ministry of Jesus and his Twelve Apostles and the Great Commission, to contemporary times and denominations. Christianity is an Abrahamic religion. It differs most significantly from the others in the claim that Jesus Christ is God the Son. The vast majority of Christians believe in a triune God consisting of three unified and distinct persons: God the Father, God the Son and the Holy Spirit. There have been significant theological differences among Christians regarding the divine and human natures of Jesus and the triune nature of God. These differences continue today.

In many Christian denominations "The Church" is understood theologically as the institution founded by Jesus for the salvation of humankind. This understanding is shared between Catholic and Orthodox traditions. They see in the Church a foundation of Christ, who continues to live in it, through the Holy Spirit. In the Catholic tradition, the Catholic Church is the Body of Christ. Protestant churches generally view all Christians to be the Body of Christ. Some Protestant theologians call this High Church. In contrast, Low Church denominations generally emphasise the personal relationship between a believer and Jesus Christ. Other Christians, however, would say that the Church is not an institution at all. Instead, it is the gathering of believers, individually, and ultimately in heaven where all believers from all nations and times will be gathered together; so, church history is not just about the history of institutions, but the major happenings amongst believers throughout the world, throughout time.

Christianity began in 1st century AD Jerusalem. Luke states in Acts 2:5-11 that there were present in Jerusalem on the day of Pentecost “devout men from every nation under heaven... Parthians, Medes, Elamites, (regions of present-day Iran), residents of Mesopotamia, Judea and Cappadocia, Pontus (both in Ancient Greece, present-day Turkey) and Arabians”. It spread initially in the Near East, ultimately becoming the state religion of Armenia in either 301 or 314, of Ethiopia in 325, of Georgia in 337, and then the state religion of the Roman Empire in 380 (see Edict of Thessalonica). During the Age of Exploration (15th to 17th cent.), Christianity expanded throughout the world, becoming the world's largest religion.

Throughout its history, the religion has weathered schisms and theological disputes that have resulted in many distinct churches. The largest branches of Christianity are the Roman Catholic Church and the Eastern Orthodox Church, and the Protestant churches.