Which core Christian beliefs did Origen accept in De principiis?

In his work De principiis (On First Principles), Origen operated under the presupposition that every Christian is committed to the "rule of faith" established by the Apostles. He accepted the following core Christian beliefs as foundational, while maintaining that educated believers were free to speculate on matters outside these specific restrictions:1

• The Nature of God: The belief that the Creator is the one God of both the Old and New Testaments.1
• The Incarnation: The belief in the incarnation of the preexistent Lord.1
• The Trinity: The recognition of the Holy Spirit as one of the divine triad.1
• Human Nature and Agency: The belief in the freedom of rational souls.1
• Spiritual Reality: The existence of discarnate spirits.1
• Cosmology and Eschatology: The belief in the noneternity of the world and the reality of a judgment to come.1

Origen viewed these tenets as the essential boundaries of the faith, distinguishing them from the broader, speculative theological arguments that characterized his wider body of work.12