By Middle East correspondent Frank Gardner

Pope John Paul II's visit to Egypt is the first in 2000 years of Christianity by a pontiff from Rome.

Nearly 90% of Egypt's 64 million people are Muslims, with the vast majority following the mainstream Sunni branch of Islam.

But the country also has the largest and oldest Christian community in the Middle East.

Complex community

Egyptian Christians are known collectively as 'Copts', a word derived from the Greek word 'Aigyptos', meaning 'Egypt'.

They trace their history to the first century AD when St Mark introduced Christianity to Egypt.

This Christian community is divided into several groups: Coptic Orthodox, Coptic Catholics, Coptic Evangelicans (Protestants) and other minorities.

The largest group of Egyptian Christians belongs to the Coptic Orthodox church.

They number 6-7 million and account for an estimated 93% of Egypt's Christians.

Own pope

They have their own pope, Pope Shenouda III, and give allegiance to him rather than to Rome.

Orthodox Copts are patriotically Egyptian and some even resent the coming visit by a Pope from Rome, seeing it as a form of global domination by the Vatican.

Prominent Orthodox Copts include the former UN Secretary General Boutros Boutros Ghali and the heart surgeon Dr Magdy Yacoub.

Independent from Rome

Egypt's Catholics are nearly all 'Coptic Catholics', a group independent from Rome.

They number between 200,000 and 250,000 and are led by Patriarch Stephanos II Ghattas, although they see the Pope in Rome as their spiritual leader.

Their community dates from the days of French and British colonisation of Egypt, and today they run over 150 schools throughout the country.

The coming visit by Pope John Paul II means the most to them, and some Coptic Catholics have already begun travelling hundreds of kilometres from southern Egyptian villages to Cairo for the open-air mass on Friday.

Roman Catholics

Egypt's Roman Catholics are thought to number less than a thousand.

The Coptic Evangelicans are the Protestants of Egypt and they number around 150,000.

They have close historic links with churches in America, dating back to the work of nineteenth century missionaries.

Today they are heavily involved in education and healthcare for low-income Egyptians.

Orthodox

Greek Orthodox Christians number only a few thousand, down from a peak of 150,000 two centuries ago.

Their decline was spurred by the nationalisation policies of Egypt's first president, Gamal Abdul Nasser.

The best-known Greek Orthodox Christians in the country are the monks who inhabit the fortified Monastery of St Catherine high on Mt Sinai.

This site will form the climax of Pope John Paul II's Egyptian visit on Saturday as he performs what the Vatican is calling "a Jubilee Pilgrimmage" to celebrate the millennium.

Like the Orthodox Copts, these monks owe no allegiance to Rome and the Vatican, and Pope John Paul II has not been allowed to hold mass inside the monastery.

Minorities

The remaining Christian communities make up a tiny minority, totalling a few thousand.

Because of the historic rivalry between the Orthodox and Catholic branches of the Christian faith, Pope John Paul II's visit is controversial for some Egyptian Christians.

While they welcome him as a man of peace, they fear the massive media attention will give the impression that Egypt's own Pope Shenouda III is somehow subordinate to Rome.

Nationalism is deeply ingrained in Egyptian Christianity and is likely to remain so.