Most Americans probably think of Christianity as either Protestant or Latin Rite Roman Catholic. They may have a vague understanding of “Orthodoxy,” which they identify with the Greeks, Russians, or other Eastern Europeans. But, by and large, “Christianity” means the Latin West or, to a lesser extent, the Greek (and Cyrillic) East. As generalizations go, this one is not terribly far from the mark. Out of the estimated 2.2 billion Christians in the world, the vast majority are Roman Catholic (1.1 billion), Protestant (800 million) or Orthodox (200 million). Most of the Orthodox are Russian (150 million) or Greek (25 million.)
The problem with this view is that it obscures the importance of other groups in Christian history. At one time, Christianity spread widely across Asia Minor, Africa, the Middle East, and Europe. Coptic, Syriac, Persian and Arabic were more important to many Christians than Latin or Greek. Around the year 800, for example, about one quarter of the world’s Christians looked to the Syriac/Arabic speaking Catholicos (Patriarch) of Bagdad as their spiritual leader. Coptic Christianity was the majority religion in Egypt until the 10th century, and had wide influence in Ethiopia, Syria, and even into India.
Some of these Churches broke off from the Catholic Church, but not all. The Maronites of Lebanon and Syria provide an outstanding example of fidelity to the Pope. In 517, the Monastery of St. Maron could address Pope Hormisdas as “Hormisdas, the most holy and blessed patriarch of the whole world, the holder of the See of Peter, the leader of the apostles.” During the 11th century, at the same time that Constantinople was rebuffing Rome, the Maronites reaffirmed their unity with the Holy See. Pope Pascal II gave crown and staff to the Maronite Patriarch Youseff Al Jirjisi in 1100 A.D. Innocent III likewise recognized the authority of their Patriarchate, and a Maronite bishop was present at the Fourth Lateran Council in 1215.
Even those groups that broke away from the Pope were very important in the development of Catholic doctrine. Alexandria (Egypt) gave us the Church’s first systematic theologians and their influence was widely felt at the council of Nicaea. Egyptian monks were strong supporters of Nicene orthodoxy and their example of monasticism spread throughout the world. Syriac Christians have transmitted some of the greatest hymns and liturgies in the Church. We are indebted to all these Christians for the development of devotion to the Mother of God.
The rise of Islam caused great damage to these Christian communities. They no longer have anything like the numerical significance they once did. But their witness remains important for many reasons. One reason is that they are an important witness to the principle of tradition, even when they broke fellowship with the Pope. If you compare the “Lost Christianities” to modern, “Bible-alone” Protestantism, you find stark differences. All the ancient Christian communities (even the non-Catholic ones) acknowledge the authority of priests, bishops, and patriarchs. They believe in apostolic succession. They practice a liturgical, Eucharistic spirituality. They pray for the dead. They venerate the saints.
These communities also witness to the importance of the Papacy even when they had previously broken with the Pope. In 2008, some Assyrian Christians sought reunion with the Pope because of their own liturgical and canonical tradition. Their Bishop Mar Bawai Soro said he was impressed with the prominent role ascribed to St. Peter and the Church of Rome in the history of the Assyrian Church.
Finally, these Churches are important because they demonstrate that Tradition alone is no more effective than Scripture alone in achieving Church unity. When these ancient communities broke fellowship with the wider Christian world, they did so in the name of tradition and antiquity. But some of them forgot that Catholicity is also a mark of the true Church. The Church is a visible unity spread across the globe. The true church cannot be simply the Church of the East, or the Church of the Copts, or the Russians, or the Lutherans or the Calvinists. Nor is it simply an ethereal, invisible, “spiritual” community of believers. As St. Augustine once said, the verdict of the whole world is conclusive! And this verdict can only be realized when there is a visible center of unity. For this reason, we need not only Scripture and tradition, but also the living Magisterium of the Church.
Non-Catholic historian Philip Jenkins has written an enjoyable book on these ancient Christian communities: The Lost History of Christianity: The Thousand-Year Golden Age of the Church in the Middle East, Africa, and Asia–and How It Died. Dominican theologian Aidan Nichols also treats them in his book Rome and the Eastern Churches.