The first person of the Trinity, God the Father, is the ‘fountain’ of the Godhead, the source, cause or principle of origin for the other two persons. He is the bond of unity between the three: there is one God because there is one Father. ‘The union is the Father, from whom and to whom the order of the persons runs its course’ (St Gregory the Theologian). The other two persons are each defined in terms of their relationship to the Father: the Son is ‘begotten’ by the Father, the Spirit ‘proceeds’ from the Father. In the Latin West, it is usually held that the Spirit proceeds ‘from the Father and from the Son’; and the word filioque (‘and from the Son’) has been added to the Latin text of the Creed. Orthodoxy not only regards the filioque as an unauthorized addition – for it was inserted into the Creed without the consent of the Christian East – but it also considers that the doctrine of the ‘double procession’, as commonly expounded, is theologically inexact and spiritually harmful. According to the Greek Fathers of the fourth century, whom the Orthodox Church follows to this day, the Father is the sole source and ground of unity in the Godhead. To make the Son a source as well as the Father, or in combination with him, is to risk confusing the distinctive characteristics of the persons.