Why did Catholicism and Protestantism split?

Historical background

During the period of persecution, the Early Christian Church developed differently according to the part of the Roman Empire; the Church in the East developed differently from the West and the Church in Africa (Copts) differed again. After the legalisation of Christianity, the Church came to accept that there were 3 main leaders (Patriarchs): the bishops of Alexandria, Antioch and Rome. To these were added the bishop of Constantinople (by the Council of Constantinople in 381) and the bishop of Jerusalem (by the Council of Chalcedon in 451).

With Constantine's transfer of the capital of the Empire to Constantinople, the Empire was effectively split into two sections: East and West. (Diocletian formally divided the Empire into 2 sections in early part of the 4th century)

The Church

When the western part of the Empire fell into decay, and was eventually overrun by invaders, the political, judicial and social responsibilities of its officials were assumed by the leaders of the Church in the West, centred on Rome. Inevitably, this dual responsibility led to a centralisation and codification of the manner in which things were done in the Western part of the Church. The Church in the East, largely unaffected by the collapse of the Western Empire, continued to be less centralised.

As time progressed, the Bishop of Rome (acknowledged by the others as being First Among Equals) began to claim greater authority due to the apostles Peter and Paul being martyred in that city. This claim was refuted by the other patriarchs. However, Rome's position became strengthened when the spread of Islam effectively isolated and diminished the influence the Patriarchs of Alexandria, Antioch and Jerusalem, leaving Rome and Constantinople in something of a state of rivalry.

A further cause of tension arose when the Western Church inserted the "filioque" into Nicene Creed. Traditionally, the Holy Spirit was seen to proceed from God the Father; the insertion of the "filioque" clause meant that, in the West, the Holy Spirit was believed to proceed from God the Father and God the Son. For the Church in the East, Rome had overstepped its authority by altering a Creed which had been approved by an ecumenical council. In 867 the Patriarch of Constantinople (Photius I)declared the insertion to be heretical, thereby accusing the Patriarch of the West (the Bishop of Rome) of heresy.

Other factors also caused the East and West to drift apart: language, different manners of liturgical celebration, different approaches to solving ecclesiastical conflict, different ways of explaining doctrine and the gradual imposition of clerical celibacy in the West.

The consummation of the schism is generally dated to 16 July 1054 due to a disagreement between the Patriarch of Constantinople and the papal legate who had been sent to solve a disagreement several matters: the type of bread to be used in the Eucharist, the claim to greater power by the Bishop of Rome and the Patriarch's use of the title "Ecumenical". Humbert felt insulted by the treatment he had received from the Patriarch who, apparently, kept him waiting. Although the pope (Leo IX) had been dead for some 3 months (and thus the legate's authority had ended) Humbert decided to excommunicate Patriarch Michael; the Patriarch reciprocated. It is rather simplistic to state that the East-West Schism occurred in 1054, as it had been developing for some time and it was clear that neither excommunication of 1054 included anyone other that the Patriarch, his followers and Cardinal Humbert; they did not apply to the churches.

In reality little changed in the lives of ordinary Christians or the clergy. The two churches continued to drift apart with the rise of nation states in the West (the Byzantine Empire continued) and the disaster of the Fourth Crusade when the crusaders attacked and looted Constantinople. There were futile attempts at reconciliation.

In brief, the schism between East and West developed over centuries and the reasons are several: linguistic, societal, judicial, ecclesiastical, political and theological. (PLease see related links)

The view held by religious authorities in the mainly Greek-speaking eastern regions was that there were 5 senior leaders, or Metropolitans, in the Christian Church, one of whom was the bishop of Rome. However, the bishop of Rome, known in the West as the Pope, insisted that he had greater authority than the other Metropolitans. Gradually, differences built up, but the key points of difference were an attempt by the bishop of Rome to change the Nicene Creed without a further Council of bishops, and Rome's objection to the Eastern churches allowing married priests.

The Great Schism resulted when Pope Leo IX sent legates to Patriarch Michael I, they attempted to excommunicate Michael and he then excommunicated the legates (Leo having died, Michael was unable to excommunicate him). There were attempts at reconciliation and the Churches came close to being reunited in 1274 and in 1439, but the schism eventually became permanent.

The western Church, based on Rome, has become known as Roman Catholic, while the eastern Churches have become known as Orthodox Churches.

Mainly because these two churches had minor disagreements. For example, Eastern Orthodox have different Holy Comunnion traditions. There are many differences. Catholic priests can not have children, but Eastern Orthodox priests can. Believe me, I believe in the Eastern Orthodox faith.