Filioque is a Latin word meaning ‘and from the Son’. References to filioque most often refer to the word’s appearance in the third article of medieval Western Christian formulations of the Nicene-Constantinopolitan Creed (NCC) after the words ‘proceeding from the Father’. As such, filioque characterises the relationship of the Holy Spirit to the other two persons of the Trinity. While the Father begets the Son and the Son is begotten of the Father, the Holy Spirit proceeds from the Father and the Son. This ‘double procession’ of the Holy Spirit helps Western Christian theologians to explain how one God exists in three persons. The filioque distinguishes Western Christian approaches to Trinitarian theology from Eastern ones.