Filioque (/ˌfɪliˈkwi, -kw/ FIL-ee-OH-kwee, -kway; Ecclesiastical Latin: [filiˈokwe]) is a Latin term ("and from the Son") added to the original Niceno-Constantinopolitan Creed (commonly known as the Nicene Creed), and which has been the subject of great controversy between Eastern and Western Christianity. It is a term that refers to the Son, Jesus Christ, as an additional origin point 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", without additions of any kind, such as "and the Son" or "alone".[1]

The doctrine of the Filioque, from the Boulbon Altarpiece [fr]: The Holy Spirit coming from the Father and the Son, detail of the Boulbon Altarpiece, 15th century, Louvre, Paris. Provence, c. 1450. From the high altar of the chapelle Saint-Marcellin [fr], Boulbon, France.

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[2][full citation needed] 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.[3][full citation needed] This was incorporated into the liturgical practice of Rome in 1014, but was rejected by Eastern Christianity.

Whether that term Filioque is included, as well as how it is translated and understood, can have important implications for how one understands the doctrine of the Trinity, which is central to the majority of Christian churches. For some, the term implies a serious underestimation of God the Father's role in the Trinity; for others, its denial implies a serious underestimation of the role of God the Son in the Trinity.

The term has been an ongoing source of difference between Eastern Christianity and Western Christianity, formally divided since the East–West Schism of 1054.[4] There have been attempts at resolving the conflict. Among the early attempts at harmonization are the works of Maximus the Confessor, who notably was canonised independently by both Eastern and Western churches. Differences over this and other doctrines, and mainly the question of the disputed papal primacy, have been and remain the primary causes of the schism between the Eastern Orthodox and Western churches.[5][6]