At the outset the author points out that in the ancient Church belief in the Holy Spirit was inseparable from the belief in the Holy Trinity, which is confirmed by baptismal creeds and liturgical anaphorae. He then underlines the significance of the Cappadocian theology and the Second Ecumenical Council for the final formulation of the Church's faith with regard to the Holy Spirit.

Further, the author envisages the historical and theological context of the Trinitarian doctrine of the Cappadocian Fathers, especially their pneumatology. He indicates the difference in approach to the Trinitarian theology between East and West and the different ways of theological strategy in struggling against main anti-Trinitarian haereses during the III and IV centuries: Monarchianism, on one hand, and Arianism as well as Macedonianism, on the other one.

The author emphasizes the immense theological significance of the Cappadocian Fathers for the Triadological and Pneumatological theology of the Church. The Cappadocians found the straight way and exact expression of the Church’s traditional faith, so as to escape the various haeretical errors and theological exaggerations both in the East and in the West. Therefore, their Trinitarian confession, — entirely taken from the Eastern tradition, but rightfully called the „Neo-Nicene”, — is accepted by the whole Church ecumenical, not merely as a theology of one »school«, but as a theological expression of the ecclesial self-knowledge, as a »rule of faith« solemnly sealed in the Nieene-Constantinopolitan Creed at the Second Ecumenical Council. As such it becomes the basis for all posterior Christo- logical teaching of the Church.

Contrary to this inspired way of theologizing there will appear in the West a different teaching on the Holy Trinity and the Holy Spirit, which will represent a deviation from the Cappadocian Tniadology and consequently from the Church's faith. This stream of thinking led to the well-known doctrine of Filioque in the Mediaeval Western Scholasticism. The initiator of this Western doctrine was Augustine of Hippo, whose doctrine on the Holy Spirit will be treated in the next issue.