Are "Christianity," "Catholicism," and "Eastern Orthodoxy" all the same thing? This first article in the Worldviews Series starts with Judaism as the shared root and traces the full story of the Christian faith — from the unity of the early church, through the Great Schism of 1054, to the sixteenth-century Reformation. It clears up common confusion around the terms "Christianity," "Christian religion," and "Protestantism," and compares the key differences among Catholicism, Eastern Orthodoxy, and Protestantism in authority, salvation, and church governance. The goal is to help brothers and sisters better understand the Christian neighbours around them who come from different traditions.

One Tree, Three Great Branches

— The Origins and Distinctions of Judaism, Catholicism, Eastern Orthodoxy, and Protestant Christianity

Written for brothers, sisters, and friends who want to make sense of these terms. This is not meant to be exhaustive — the goal is a clear overview that is faithful to the facts.

Part One: Clearing Up a Common Confusion

In everyday English, the word "Christianity" can be used in two different ways:

Broadly: referring to all faiths that believe in Jesus Christ, including Catholicism, Eastern Orthodoxy, and Protestantism. Scholars sometimes use the term "the Christian religion" or "Christendom" in this sense.
Narrowly: referring specifically to Protestantism — the tradition that emerged from the sixteenth-century Reformation, and the one most of us in evangelical and Chinese-heritage churches belong to.

In this article, we will use the term "Protestantism" (or "Protestant Christianity") for this specific branch, to avoid confusion.

Part Two: The Root — Judaism, Where It All Begins

The Christian faith did not appear out of nowhere. Its root is Judaism.

Judaism is the faith described in the Old Testament — the covenant God made with Abraham and his descendants. Jewish people believe that Yahweh is the one true God, the Creator of the universe and everything in it — that He brought all things into existence out of nothing (Genesis 1:1). Humanity fell into disorder, sin, and suffering through rebellion against the Creator. God gave the Law through Moses and promised the coming of the Messiah (the Savior).

It is worth pausing here to note something important: the God of the Bible is fundamentally different from the various deities found in popular folk religion. Folk deities — whether Guan Yu, Mazu, or the Earth God — are not creators; in their own legends they are themselves created beings. The God of the Bible, Yahweh, is the source and Creator of all things. If we were to look for a parallel concept in traditional Chinese culture, the closest would actually be the ancient Chinese reverence for "Heaven" (天, Tiān) — the supreme, transcendent power above all things, who governs the universe and rewards good and punishes evil. The God of the Bible, however, has revealed Himself far more fully and clearly than the concept of "Heaven" ever did.

The defining fork in the road: When Jesus came, some Jewish people believed He was the Messiah God had promised, and these became the first Christians. But the majority of Jewish people did not accept Jesus as the Messiah and have continued in the Jewish tradition to this day.

In short: Judaism and Christianity worship the same God and share the same Old Testament. The dividing question is: "Is Jesus the Messiah?"

Part Three: The Trunk — The Early Church, a Thousand Years of Unity

The church was born at Pentecost (Acts 2). For roughly the first thousand years, despite cultural and liturgical differences across regions, there was essentially one church, united in the apostolic teaching and the core doctrines established by the great ecumenical councils (such as the Council of Nicaea).

Over time, however, as the Roman Empire divided into eastern and western halves, the church gradually developed two centers:

The West: centered in Rome, led by the Pope, using Latin.
The East: centered in Constantinople, led by the Patriarch, using Greek.

Theological differences, liturgical traditions, and disputes over authority grew increasingly sharp between the two.

Part Four: The First Great Split (1054) — Catholicism and Eastern Orthodoxy Part Ways

In AD 1054, the Eastern and Western churches formally broke from each other, each excommunicating the other. This is known in church history as the Great Schism. From that point on:

	Roman Catholicism (West)	Eastern Orthodoxy (East)
Center	Rome	Constantinople (modern Istanbul)
Highest Authority	The Pope, regarded as the universal head of the church	No single supreme leader; patriarchs of each region hold equal standing
Liturgical Language	Latin	Greek, Slavonic, and others
Main Geographic Presence	Western Europe, Southern Europe, Latin America	Eastern Europe, Russia, Greece, the Middle East
Theological Emphases	Papal authority, purgatory, and other distinctive doctrines	Mystical tradition, veneration of icons, unity within diversity

The core beliefs of both traditions — the Trinity, the two natures of Christ, salvation, and so on — are actually quite close. The differences lie more in church governance and liturgical practice.

Part Five: The Second Great Split (1517) — Protestantism Emerges from Catholicism

Many people think of the medieval church primarily in terms of its failures. But this is an oversimplification. In truth, the medieval church made an enormous contribution to the shaping of Western civilization:

After the Western Roman Empire collapsed in AD 476, Europe fell into prolonged political instability. In an era when secular power had fragmented, the church became the central force holding European society together — providing a shared moral framework, mediating conflicts, sustaining community life, and in many places effectively performing the functions of government.
Monasteries preserved classical manuscripts and scholarly traditions, keeping the flame of learning alive. They also cleared land, developed agricultural techniques, and became pillars of local economies.
Europe's earliest universities — Paris, Oxford, Cambridge — were all founded by the church. The roots of the modern university lie in the church.
The church built hospitals and systems of care for the poor across Europe. The very idea that society should care for the sick and the destitute is a direct fruit of Christian ethics.
Canon Law is one of the important foundations of the modern Western legal tradition.
The breathtaking Gothic cathedrals were not only architectural marvels but also drove advances in engineering and the arts.

It is fair to say that without the church, Europe after the fall of Rome might have descended into far deeper and longer-lasting chaos.

The Spark That Lit the Reformation

That said, by the late medieval period, serious problems had developed within the Catholic Church: the selling of indulgences, the buying and selling of church offices (simony), and the fact that ordinary believers had no access to the Bible in their own languages (only a Latin translation existed).

In 1517, a German monk named Martin Luther nailed his Ninety-Five Theses to a church door, publicly challenging these practices. This ignited the Reformation. Reformers such as John Calvin and Ulrich Zwingli soon joined the movement, and Protestantism was born.

The Five Solas

The core convictions of Protestantism are summarized in the Five Solas:

Sola Scriptura (Scripture Alone) — the Bible is the supreme authority for faith and life
Sola Fide (Faith Alone) — justification is by faith, not by works
Sola Gratia (Grace Alone) — salvation comes entirely from God's grace
Solus Christus (Christ Alone) — Christ is the only mediator between God and humanity
Soli Deo Gloria (To God Alone Be Glory) — all glory belongs to God

Part Six: A Comparison of the Three Traditions

Issue	Catholicism	Eastern Orthodoxy	Protestantism
Highest Authority	Pope + Scripture + Sacred Tradition	Scripture + Sacred Tradition + Ecumenical Councils	Scripture Alone
Way of Salvation	Faith + Works + Sacraments	Faith + Union with God (theosis/deification)	Justification by Faith Alone
The Virgin Mary	Highly venerated; several distinctive Marian doctrines	Venerated as Theotokos ("God-bearer"); fewer formal doctrines	Respected, but not prayed to or worshipped
Intercession of Saints	Accepted	Accepted	Generally not accepted
Sacraments	Seven sacraments	Seven sacraments	Two: Baptism and the Lord's Supper
Clergy	Pope — Cardinals — Bishops — Priests (celibate)	Patriarchs — Bishops — Priests (may marry)	Pastors (may marry); the priesthood of all believers emphasized
Purgatory	Affirmed	Not affirmed	Not affirmed

Part Seven: A Diagram to Help You Remember

        Judaism (Old Testament faith, awaiting the Messiah)
               │
               │ Jesus came ✝️
               │
          Early Church (one united church)
               │
         ──────┴──────
         │            │
    Western Church   Eastern Church
      (Latin)          (Greek)
         │            │
         │    Great Schism, 1054
         │            │
      Catholicism   Eastern Orthodoxy
         │
         │  Protestant Reformation, 1517
         │
      Protestantism
         │
    ┌────┼────┬────┐
  Lutheran Reformed Baptist  …

Part Eight: A One-Sentence Summary

Judaism is the root; the early church is the trunk. In 1054, the trunk divided into two great branches: Catholicism and Eastern Orthodoxy. In 1517, a new branch — Protestantism — grew out of the Catholic branch. All three affirm the Triune God and confess Jesus as the Christ. Their differences lie primarily in the source of authority, the way of salvation, and the governance of the church.

Most of our churches in the evangelical and Chinese-heritage tradition belong to the Protestant stream. Understanding this history is not about judging which tradition is right. It is about helping us understand where our own faith comes from — and equipping us to engage wisely and graciously with brothers and sisters from other traditions.

This article is a brief introduction. For deeper study, the following are recommended:

Williston Walker, A History of the Christian Church
Earle E. Cairns, Christianity Through the Centuries

💬 After reading this article, if you have any thoughts or questions, you are welcome to ask Pastor Bond:

"Are Christianity, Catholicism, and Eastern Orthodoxy all the same thing?"

"What exactly is the difference between 'Christianity' and 'Protestantism'?"

"I have Catholic or Orthodox friends — how should I think about their faith?"

One Tree, Three Great Branches — A Simple Guide to Judaism and the Three Major Christian Traditions