Chapter 1 — The Creed
Section 6. Note on the Filioque: This text includes the phrase 'and the Son' (Latin: filioque), as used in Western churches since the Council of Toledo (589 AD) and formally adopted in the West by 1014 AD. The original text of the 381 Council of Constantinople reads 'who proceeds from the Father' only, and is the version used in Eastern Orthodox churches to this day. The filioque was a contributing factor in the Great Schism of 1054 between East and West.