1 min read 148 words Updated Sep 05, 2026 Created Sep 05, 2026
#church-history#councils#theology#tier2

First Council of Nicaea (325)

Background

Key figures

What was condemned

Arianism (the teaching that the Son is a created being, not eternally God)

What was defined

The Son is homoousios (of one essence) with the Father — origin of the Nicene Creed

Aftermath and reception

Primary sources

  • Full primary texts (definition + canons, NPNF2-14): nicaea_i_325

Reading notes