On the First Principles (Greek: Περὶ Ἀρχῶν / Peri Archon; Latin: De Principiis) is a theological treatise by the Christian writer Origen.
When Origen was around forty-five years of age, he interrupted his burgeoning program of scriptural exegesis to write Peri Archon.
In this work he provided a unified discussion of Christian teachings so that his readers could probe more deeply into the church's rule of faith and discriminate among conflicting scriptural interpretations that were swirling through Alexandria in the late 220s.
The vast majority of the text has only survived in a Latin translation produced by Tyrannius Rufinus in 397.
Book Two describes the world of man, including the incarnation of the Logos, the soul, free will, and eschatology.