Apologetic for Filioque in Medieval Theology

The original Nicene Creed (381 AD) said that the Holy Spirit 'proceeds from the Father' and the Eastern Orthodox churches follow that wording to this day. However, in the West the growing tradition was to think of the Spirit as 'proceeding from the Father and the Son' (Latin: filioque) and eventually in 589 AD the ecumenical creed of Nicea was modified by the Catholic Church to include the word 'filioque' ('and the Son'). This controversial move was the sole doctrinal cause of the Great Sch...