A Christian denomination is a religious organization (an association or fellowship) that unites local congregations in a single, legal and administrative body. Christian denominations differ in what they use for the basis of their doctrines and beliefs. Starting as one church founded by St Peter after Jesus' ascension into heaven, the first schism in the early church was between Catholicism and Eastern Orthodoxy. The two traditions began to divide, as the Roman Empire fragmented, after the seventh Ecumenical Council in 787 CE and is commonly believed to have finally split over the conflict with Rome in the so called Great Schism in 1054. The next biggest split was between Catholicism and the denominations that have roots in the Protestant Reformation. The main denominations today are Catholic, Protestant and Eastern Orthodox, but each has many sub-denominations. In 1980, 20,800 Christian denominations in the world had been identified with more than 1,000 different Christian branches in the US. These can be classified into seven major alliances and 156 ecclesiastical traditions. Christian denominations can also be categorised by whether they are fundamentalist or conservative, mainline or liberal groups. Fundamentalist/conservative/evangelical Christian groups can generally be characterized as believing that salvation is a free gift of God. It is received by repenting and asking for forgiveness of sin and trusting Jesus as Lord and Saviour. Christian denominations also differ in what they use for the basis of their doctrines and beliefs. The biggest split is between Catholicism and the denominations that have roots in the Protestant Reformation. All denominations views their own as the ‘true doctrine’.