Catholic, Orthodox and Protestant: how Christianity divided

In its first centuries Christianity spread across the Roman Empire and beyond, east into Persia and south into Egypt and Ethiopia. Great councils of bishops defined the faith. The Council of Chalcedon in 451 declared that Christ is one person in two natures, fully divine and fully human.

Churches in Egypt, Syria, Armenia and Ethiopia did not accept its wording, holding to the formula of “one incarnate nature”. They became the Oriental Orthodox churches: the Coptic, Syriac, Armenian, Ethiopian and Eritrean churches. Earlier, the Church of the East, in Persia, had separated after the Council of Ephesus in 431 and carried Christianity along the Silk Road as far as China.

The Latin-speaking West, centred on Rome, and the Greek-speaking East, centred on Constantinople, drifted apart over centuries in language, customs and politics. Two questions were sharpest: the authority of the Pope, which the East saw as first in honour among the patriarchs rather than ruler over all; and the Filioque, the Western addition to the Creed.

In 1054 papal legates and the Patriarch of Constantinople excommunicated each other. The sack of Constantinople by Western crusaders in 1204 deepened the rift. The Roman Catholic Church and the Eastern Orthodox churches have been separate ever since, though the mutual excommunications were lifted in 1965.

In 1517 the German monk Martin Luther published his Ninety-five Theses against the sale of indulgences. His teaching that salvation comes by grace through faith alone, and that scripture alone is the final authority, spread rapidly with the new printing press. Other reformers followed: Huldrych Zwingli and John Calvin in Switzerland, and in England a break with Rome under Henry VIII that produced the Church of England.

Protestant churches multiplied: Lutheran, Reformed and Presbyterian, Anglican, Baptist, Methodist and, in the 20th century, Pentecostal. The Catholic Church answered with its own reform at the Council of Trent (1545–1563).

Catholics recognise the Pope as successor of Saint Peter and head of the Church, and seven sacraments. The Orthodox, a family of self-governing churches, treasure the liturgy, icons and the tradition of the early councils. Protestants stress the Bible, preaching and the faith of the individual believer, and most recognise two sacraments, baptism and the Lord’s Supper.

Since the 20th century the ecumenical movement has brought them closer. Christians of every family still share the creeds of the first centuries, the Lord’s Prayer and the hope of the resurrection.