Different interpretations of the Holy Trinity divided Eastern and Western Christendom.
Different interpretations of the Holy Trinity divided Eastern and Western Christendom.

There was not just one reason for the splitting of the medieval Christian church, but a large contributing factor in the “Great Schism” of 1054, which divided the Roman Catholic Church and the Eastern Orthodox Church, was the Nicene Creed. More specifically, there was one point of contention with the Nicene Creed: the Holy Trinity.

The Council of Nicea

In 325, the young religion of Christianity was not the well-oiled organization it is today. Constantine had just become the first Christian leader of the Roman Empire and in doing so, assumed responsibility for a religion in the throes of warring factions. The source of the conflict wrested largely on the question of Jesus' divinity.

At Constantine's behest, 318 bishops of the empire descended on the Turkish town of Nicea to hammer out a common understanding on whether Jesus was eternally divine like God or a remarkable, yet mortal, man. The compromise of Nicea proffered that Jesus and God were of the same “substance,” a standing codified in the Nicene Creed.

Nicene Creed

That creed forms the fundamental basis of Christianity (Catholic, Orthodox and Protestant) today. The text outlines the bishops' belief in one God, Jesus Christ, “the Only Begotten Son of God,” and the Holy Spirit. (The creed also includes the belief in one church, a tenet to be tested within a century.) The creed, as read today, was revised and expanded at the Second Ecumenical Council in Constantinople in 381.

Filioque

In the ensuing century — though the exact date or party responsible is disputed — the phrase “and the Son” crept into the Nicene Creed's statement on the Holy Spirit: “I believe in the Holy Spirit, the Lord, the giver of life, who proceeds from the Father and the Son.” The phrase, known by its Latin translation “filioque,” was incorporated increasingly in Western liturgies.

The inclusion of the filioque phrase speaks to a fundamental difference in the Eastern and Western understandings of the Holy Trinity. In the Eastern Church it was the Father from whom both the Son and Holy Spirit flow; the Western Church possessed a flattened hierarchy in which all three are unified by divine essence, which diminishes the role of the Father in the eyes of Easterners.

East vs. West

The presence of the filioque phrase in Western texts of the Nicene Creed “scandalized” Eastern Christians, as the United States Conference of Catholic Bishops notes. But the Great Schism of Eastern and Western Christendom was the result of several rifts that grew cataclysmic, ultimately magnifying the importance of filioque. The geographic and linguistic divide between the two factions — the Western Church centered in Rome and the Constantinople-based Eastern Church's resentment of papal authority — contributed much of the ammunition for the Great Schism of 1054 and exacerbated any theological disputes. Nonetheless, the difference between Eastern and Western interpretations of the Holy Trinity played its part in breaking the Eastern Orthodox Church from the Roman Catholic Church.