History of the filioque controversy

The history of the filioque controversy is the historical development of theological controversies within Christianity regarding three distinctive issues: the orthodoxy of the doctrine of procession of the Holy Spirit as represented by the Filioque clause, the nature of anathemas mutually imposed by conflicted sides during the Filioque controversy, and the liceity (legitimacy) of the insertion of the Filioque phrase into the Nicene Creed. Although the debates over the orthodoxy of the doctrine of procession and the nature of related anathemas preceded the question of the admissibility of the phrase as inserted into the Creed, all of those issues became linked when the insertion received the approval of the Pope in the eleventh century.