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The Library

Foundational Writings

The texts themselves — treatises, confessions, mystical journeys, and manifestos that shaped Christian thought. Click any volume to enter the reader.

Confessions
Confessions
Augustine of Hippo · c. 397–400
Autobiography / Theology

A searching autobiographical prayer tracing Augustine's conversion from restlessness to rest in God.

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The City of God
The City of God
Augustine of Hippo · 413–426
Theology / Political Philosophy

Written after the sack of Rome, contrasting the earthly city built on self-love with the City of God built on love of God.

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Summa Theologiae
Summa Theologiae
Thomas Aquinas · 1265–1274
Systematic Theology

A vast dialectical synthesis of theology addressed to beginners, treating God, creation, ethics, and Christ.

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On First Principles
On First Principles
Origen of Alexandria · c. 220–230
Systematic Theology

The first systematic Christian theology, treating God, creation, free will, and the soul.

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The Ninety-Five Theses
The Ninety-Five Theses
Martin Luther · 1517
Disputation / Reform Document

Luther's academic theses against the sale of indulgences, the spark of the Protestant Reformation.

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The Interior Castle
The Interior Castle
Teresa of Ávila · 1577
Mystical Theology

Maps the soul as a castle of seven mansions through which the believer journeys toward union with God.

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Church Dogmatics
Church Dogmatics
Karl Barth · 1932–1967
Systematic Theology

An unfinished, multi-volume systematic theology centered entirely on God's self-revelation in Jesus Christ.

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On the Incarnation
On the Incarnation
Athanasius of Alexandria · c. 318
Christology

A foundational defense of why the Word became flesh to restore fallen humanity.

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Institutes of the Christian Religion
Institutes of the Christian Religion
John Calvin · 1536–1559
Systematic Theology

The most systematic and enduring statement of Reformed theology, from the knowledge of God to church order.

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