Third Ecumenical Council

Council of Ephesus

431 · Ephesus · convened under Theodosius II

Historical context

Convened against Nestorius, who divided Christ into two persons.

Major decisions

  • Affirmed Christ as one divine Person.
  • Defined Mary as Theotokos (God-bearer).

Canons

8 canons addressing Nestorianism and Pelagianism.

Long-term impact

Christ's personal unity established; Marian devotion grounded christologically.