Coptic Church, the major Christian church in Egypt, the name of which, derived from the Greek word for "Egyptian- (Arab., qubt, Westernized as Copt), points to its national origins. Unsubstantiated tradition attributes to the apostle Mark the initial preaching of Christianity in Egypt. Recent scholarship suggests that the origins of Egyptian Christianity are to be found among the Jews living in Alexandria in the 1st century AD. By the end of the 2nd century the Christian catechetical school in Alexandria, the major city of Hellenistic Egypt, headed by Clement of Alexandria had already acquired great fame. Origen, the founder of Greek Christian theology and biblical science, followed Clement as head of the school. In the 4th and 5th centuries, two great bishops of Alexandria defended Christian orthodoxy "St Athanasius, against Arianism, and St Cyril, against Nestorianism.
Some Egyptian Christians, however, refused to follow the decrees of the Council of Chalcedon (451), which defined the person of Jesus Christ as being "one in two natures-. The doctrine of "two natures- appeared to them to imply the existence of two Christs, divine and human, and was therefore tainted with Nestorianism. They upheld the terminology of St Cyril, who had spoken of "one incarnate nature of God the Word-. Those Egyptian Christians who rejected the Council of Chalcedon "a council accepted both in Constantinople and in Rome "faced charges of Monophysitism, the belief that Christ has only one nature rather than two.
Only a few Alexandrians remained faithful to Chalcedonian orthodoxy. Because this minority was supported by Byzantine imperial authorities, the Copts developed national and cultural animosity against the Byzantine Empire. This hostility facilitated the conquest of Egypt by the Arab Muslims in the 7th century. Today the Coptic Christian population of Egypt constitutes a substantial minority of about 7 million, although official government statistics reduce this figure.