Christianity is the religion founded by Jesus of Nazareth in the 1st century AD, and is centred on his life and recorded in the Bible. In the mid- 1970s the number of Christians was estimated to be more than a thousand milion world- wide. Jesus Christ (the “Annointed Saviour“) intended to reform the Judaism of his time but ended in founding a separate religion . After his crucifixion, Christianity spread throughout the Roman Empire, and during the Middle Ages the Christian Church, ruled by the pope in Rome, was the most powerful institution in Europe. A separate Church, the Eastern Orthodox Church , was centred in Constantinople. Christianity suffered a major crisis in the 16th century when there was a revolt against the authority- and some of the teaching- of the Roman Catholic Church. The result was the foundation of various Protestant Churches, differing in ritual and opposed to Rome. Meanwhile, after the fall of Constantinopleto the Turks (1452), Russia became the centre of the Eastern Orthodox Church. Christians believe in God as the creator of the world; that Jesus Christ is his son, whose perfect human life was God's way of revealing himself to mankind. However, there are great differences among the many Christian Churches.