Boulbon in the context of "Filioque"

Filioque (/ˌfɪliˈoʊkwi, -kweɪ/ FIL-ee-OH-kwee, -⁠kway; Ecclesiastical Latin: [filiˈokwe]), a Latin term meaning "and from the Son", was added to the original Nicene Creed, and has been the subject of great controversy between Eastern and Western Christianity. The term refers to the Son, Jesus Christ, with the Father, as the one shared origin of the Holy Spirit. It is not in the original text of the Creed, attributed to the First Council of Constantinople (381), which says that the Holy Spirit proceeds "from the Father" (Greek: τὸ ἐκ του Πατρὸς ἐκπορευόμενον) without the addition "and the Son".

In the late 6th century, some Latin Churches added the words "and from the Son" (Filioque) to the description of the procession of the Holy Spirit, in what many Eastern Orthodox Christians have at a later stage argued is a violation of Canon VII of the Council of Ephesus, since the words were not included in the text by either the First Council of Nicaea or that of Constantinople. The inclusion was incorporated into the liturgical practice of Rome in 1014, but was rejected by Eastern Christianity.