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The Roman Catholic Church and the Eastern Orthodox Church are two of the three main branches of historic Christianity, with Protestantism being the third. All three branches shared a common history for the first 1,000 years of the Christian church. However, in AD 1054, the so-called Great Schism occurred, marking the first major division between the Catholic and Orthodox Churches. The Orthodox Church separated from the Catholic Church over what it saw as departures from the faith. These included beliefs about salvation, an addition to the Nicene Creed regarding the Holy Spirit, the authority of the pope, and the central liturgy in Christian worship.
One primary difference between the Catholic and Orthodox churches is their understanding of salvation. The Catholic Church teaches that salvation involves forgiveness of sin, regeneration of the sinner, and sanctification of the believer. Moreover, the Catholic Church teaches that God imparts grace through seven sacraments—baptism, confirmation, the Eucharist, penance, anointing of the sick, ordination, and marriage. These sacraments are essential to the believer’s salvation and sanctification.
In contrast, the Orthodox view of salvation, called “deification,” describes a deeply transformative process in which a person becomes more godlike through grace. This concept is based on 2 Peter 1:4, where the apostle says that through God’s promises believers “may become partakers of the divine nature, having escaped from the corruption that is in the world because of sinful desire” (ESV). The Orthodox Church view of deification does not teach that people become part of God but grow to be more like Him.
In addition to their contrasting views on salvation, the Catholic and Orthodox churches also differ on the doctrine of the procession of the Holy Spirit. Although both traditions believe that the Holy Spirit is God and the third person of the Trinity, they disagree about whether He proceeds from the Father alone or from both the Father and the Son. In this context, procession refers to the eternal relationships within the Trinity.
The Catholic Church teaches that the Holy Spirit proceeds from both the Father and the Son—a doctrine expressed in the Western addition of the phrase filioque (“and the Son”) to the Nicene Creed. In contrast, the Orthodox Church believes He proceeds from the Father alone and therefore disagrees with the filioque addition. The Catholic Church argues that the Orthodox position inaccurately represents the unity of the Trinity. In turn, the Orthodox Church argues that the Catholic Church does not fully recognize the Father’s unique role within the Trinity.
Another important doctrine that divides the Catholic and Orthodox churches is the office of the pope. In Catholicism, the pope is the Vicar of Christ and the head of the church on earth, an office that Catholic tradition traces to Peter. While the Orthodox Church generally respects the pope, it does not recognize him as possessing ultimate authority over the church. Instead, the Orthodox Church views the Ecumenical Patriarch of Constantinople as “first among equals” among Orthodox bishops, rather than as an authoritative head.
A third area of difference between the Catholic and Orthodox churches concerns their liturgies. In the Catholic Church, the central liturgy is the Mass, which centers on the Eucharist. The Catholic Church teaches that the Eucharist is the most important practice in the Christian life. The term Eucharist, stemming from a Greek word meaning “thanksgiving,” refers to a memorial in which the bread and wine are believed to become the actual body and blood of Jesus.
In the Orthodox Church, the central worship service is called “The Divine Liturgy.” It also centers on the Eucharist, incorporating music, prayer, and Scripture, along with incense, icons, and other sensory elements. The Orthodox Church also holds that the bread and wine become the body and blood of Christ but purposefully avoids explaining how the transformation occurs.
Although the Catholic and Orthodox churches have important differences, they find general agreement on important theological matters. They both believe in the Trinity. They both affirm Jesus’ virgin birth, His sinless life, His miracles, His sacrificial death for sin, His physical resurrection from the dead three days later, and His eventual return. And they generally agree that God inspired the Bible through the Holy Spirit’s work through human writers.
Though the relationship between these two branches of Christianity has historically been marked by tension, separation, and accusation, since the mid-twentieth century, their leaders have made efforts to cultivate peace, friendship, and cooperation.
