What is a Trinitarian?
A Trinitarian is a Christian who believes in the Holy Trinity: one God who eternally exists as three distinct yet co-equal and co-eternal Persons — the Father, the Son, and the Holy Spirit — sharing one divine essence.
✣ A Scholarly Cartography of Christianity ✣
Nicene Atlas
Navigating the history, thought, and tradition of Christianity — from the Apostles to today.
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Symbolum Nicaeno-Constantinopolitanum
The Nicene Creed
Confessed by the whole Church since 381 AD.
We believe in one God, the Father almighty, maker of heaven and earth, of all things visible and invisible.
And in one Lord Jesus Christ, the only-begotten Son of God, begotten of the Father before all ages, light of light, true God from true God, begotten, not made, consubstantial with the Father, through whom all things were made.
Who for us men and for our salvation came down from heaven, and was incarnate of the Holy Spirit and the Virgin Mary, and became man. He was crucified also for us under Pontius Pilate, and suffered, and was buried. And the third day he rose again, according to the Scriptures. And ascended into heaven, and sitteth at the right hand of the Father. And he shall come again with glory to judge both the living and the dead, whose kingdom shall have no end.
And in the Holy Spirit, the Lord and giver of life, who proceedeth from the Father, who with the Father and the Son together is worshipped and glorified, who spake by the prophets.
And in one, holy, catholic, and apostolic Church. I confess one baptism for the remission of sins. And I look for the resurrection of the dead, and the life of the world to come.
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Definitions
The Shared Grammar of the Faith
What is Chalcedonian Christology?
Chalcedonian Christology teaches that Jesus Christ is one Person who is both fully God and fully man, with two complete natures — divine and human — united together without confusion, without change, without division, and without separation.
What is a Christian?
A Christian is a disciple of Jesus Christ who confesses the apostolic faith as summarized in the Nicene Creed, seeks to follow Him in holiness, and is united to the Church through faith, baptism, and the grace of the Holy Spirit.
The Foundations of Historic Christianity
Before exploring the traditions, discover the beliefs that have united Christians across centuries.
Doctrine of God
The Nicene Trinity
One God in three Persons.
Christianity confesses the one God as Father, Son, and Holy Spirit — three co-equal, co-eternal Persons sharing one divine essence. This is the mystery at the heart of Christian worship, confessed at Nicaea (325) and Constantinople (381).
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Person of Christ
The Chalcedon Christ
One Person in two natures — fully God and fully man.
The Definition of Chalcedon (451) confesses that Jesus Christ is one Person made known in two natures — divine and human — without confusion, change, division, or separation. It is the fence around the mystery of the Incarnation.
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Defender of the Faith
Why Athanasius Matters
The bishop who staked his life on the divinity of Christ.
Athanasius of Alexandria (c. 296–373) spent nearly half his life in exile defending the Nicene confession that the Son is truly God. Without him, the shape of the faith held by Catholics, Orthodox, and Protestants alike would look very different.
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The Christian Timeline
Open full timeline →Featured Traditions
All traditions →catholic
Catholic Church
The Catholic Church, in communion with the Bishop of Rome, is the largest body of Christians in the world.
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orthodox
Eastern Orthodox Church
A communion of self-governing churches that confess the faith of the seven Ecumenical Councils.
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protestant
Protestant Christianity
A family of traditions originating in the 16th-century Reformation; today extremely diverse.
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oriental
Oriental Orthodox Communion
The ancient Coptic, Syriac, Armenian, Ethiopian, Eritrean, and Malankara (Indian) churches — apostolic communities that parted from the Chalcedonian mainstream in 451 while confessing the same faith in different words.
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Church Fathers
All →- d. c. 99Clement of Rome
Early bishop of Rome traditionally counted among the Apostolic Fathers.
- c. 35 – c. 108Ignatius of Antioch
Bishop of Antioch martyred in Rome; wrote seven letters en route to his death.
- c. 69 – c. 155Polycarp of Smyrna
Disciple of John the Apostle and bishop of Smyrna; martyred at extreme old age.
- c. 100 – c. 165Justin Martyr
Philosopher-convert and Christian apologist beheaded in Rome.
- c. 130 – c. 202Irenaeus of Lyons
Bishop of Lyons, disciple of Polycarp; chief opponent of Gnosticism.
Ecumenical Councils
All →- 32501First Council of Nicaea
Convened to address the teaching of Arius, who held that the Son was a creature made by the Father.
- 38102First Council of Constantinople
Convened to settle continuing Arian and Macedonian controversies over the Holy Spirit.
- 43103Council of Ephesus
Convened against Nestorius, who divided Christ into two persons.
- 45104Council of Chalcedon
Convened against Eutychian monophysitism, which collapsed Christ's two natures into one.
- 55305Second Council of Constantinople
Convened to clarify Chalcedonian Christology and condemn the 'Three Chapters'.
Explore the Atlas
Doctrine Explorer
Compare Catholic, Orthodox, and Protestant teaching on the questions that divide and unite.
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Interactive Maps
Trace missions, patriarchates, and pilgrimage routes across the ancient Christian world.
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The Library
Curated primary sources — creeds, canons, letters, and treatises — from the Patristic era on.
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Early Christian Sources
Meet the earliest writings of the Church beside the New Testament, with context and quotations.
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Compare Traditions
Place two traditions side-by-side on authority, sacraments, salvation, Mary, and the saints.
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About the Atlas
An educational project presenting each tradition fairly and on its own terms.
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