The Byzantines had little appreciation of the various developments regarding the Filioque in the West between the sixth and ninth centuries. Communication grew steadily worse, and their own struggles with monothelitism, iconoclasm, and the rise of Islam left little time to follow closely theological developments in the West. However, their interest in the Filioque became more pronounced in the middle of the 9th century, when it came to be combined with jurisdictional disputes between Rome and Constantinople, as well as with the activities of Frankish missionaries in Bulgaria. When Byzantine missionaries were expelled from Bulgaria by King Boris, under Western influence, they returned to Constantinople and reported on Western practices, including the use of the Creed with the Filioque. Patriarch Photios of Constantinople, in 867, addressed a strongly worded encyclical to the other Eastern patriarchs, commenting on the political and ecclesiastical crisis in Bulgaria as well as on the tensions between Constantinople and Rome. In this letter, Photios denounced the Western missionaries in Bulgaria and criticized Western liturgical practices.
Most significantly, Patriarch Photios called the addition of the Filioque in the West a blasphemy, and presented a substantial theological argument against the view of the Trinity which he believed it depicted. Photioss opposition to the Filioque was based upon his view that it signifies two causes in the Trinity, and diminishes the mon*archy of the Father. Thus, the Filioque seemed to him to detract from the distinc*tive character of each person of the Trinity, and to confuse their relationships, paradoxically bearing in itself the seeds of both pagan polytheism and Sabellian modalism (Mystagogy 9, 11). In his letter of 867, Photios does not, however, demonstrate any knowledge of the Latin patristic tradition behind the use of the Filioque in the West. His opposition to the Filioque would subsequently receive further elaboration in his Letter to the Patriarch of Aquileia in 883 or 884, as well as in his famous Mystagogy of the Holy Spirit, written about 886.
In concluding his letter of 867, Photios called for an ecumenical council that would resolve the issue of the interpolation of the Filioque, as well as illuminating its theological foundation. A local council was held in Constantinople in 867, which deposed Pope Nicholas I - an action which increased tensions between the two sees. In 863, Nicholas himself had refused to recognize Photios as Patriarch because of his allegedly uncanonical appointment. With changes in the imperial government, Photios was forced to resign in 867, and was replaced by Patriarch Ignatius, whom he himself had replaced in 858. A new council was convened in Constantinople later in 869. With papal representatives present and with imperial support, this Council excommunicated Photios, and was subsequently recognized in the Medieval West, for reasons unrelated to the Filioque or Photios, as the Eighth Ecumenical Council, although it was never recognized as such in the East.
The relationship between Rome and Constantinople changed when Photios again became patriarch in 877, following the death of Ignatius. In Rome, Pope Nicholas had died in 867, and was succeeded by Pope Hadrian II (867-872), who himself anathematized Photios in 869. His successor, Pope John VIII (872-882), was willing to recognize Photios as the legitimate Patriarch in Constantinople under certain conditions, thus clearing the way for a restoration of better relations. A Council was held in Constan*tinople in 879-880, in the presence of representatives from Rome and the other Eastern Patriarchates. This Council, considered by some modern Orthodox theologians to be ecumenical, suppressed the decisions of the earlier Council of 869-870, and recognized the status of Photios as patriarch. It affirmed the ecumenical character of the Council of 787 and its decisions against iconoclasm. There was no extensive discussion of the Filioque, which was not yet a part of the Creed professed in Rome itself, and no statement was made by the Council about its theological justification; yet this Council formally reaffirmed the original text of the Creed of 381, without the Filioque, and anathematized anyone who would compose another confession of faith. The Council also spoke of the Roman see in terms of great respect, and allowed the Papal legates the traditional prerogatives of presidency, recognizing their right to begin and to close discussions and to sign documents first. Nevertheless, the documents give no indication that the bishops present formally recognized any priority of jurisdiction for the see of Rome, outside of the framework of the Patristic understanding of the communion of Churches and the sixth-century canonical theory of the Pentarchy. The difficult question of the competing claims of the Pope and the Patriarch of Constantinople to jurisdiction in Bulgaria was left to be decided by the Emperor. After the Council, the Filioque continued to be used in the Creed in parts of Western Europe, despite the intentions of Pope John VIII, who, like his predecessors, maintained the text sanctioned by the Council of 381.
A new stage in the history of the controversy was reached in the early eleventh century. During the synod following the coronation of King Henry II as Holy Roman Emperor at Rome in 1014, the Creed, including the Filioque, was sung for the first time at a papal Mass. Because of this action, the liturgical use of the Creed, with the Filioque, now was generally assumed in the Latin Church to have the sanction of the papacy. Its inclusion in the Eucharist, after two centuries of papal resistance of the practice, reflected a new dominance of the German Emperors over the papacy, as well as the papacys growing sense of its own authority, under imperial protection, within the entire Church, both western and eastern.
The Filioque figured prominently in the tumultuous events of 1054, when excommunications were exchanged by representatives of the Eastern and Western Churches meeting in Constantinople. Within the context of his anathemas against Patriarch Michael I Cerularios of Constantinople and certain of his advisors, Cardinal Humbert of Silva Candida, the legate of Pope Leo IX, accused the Byzantines of improperly deleting the Filioque from the Creed, and criticized other Eastern liturgical practices. In responding to these accusations, Patriarch Michael recognized that the anathemas of Humbert did not originate with Leo IX, and cast his own anathemas simply upon the papal delegation. Leo, in fact, was already dead and his successor had not been elected. At the same time, Michael condemned the Western use of the Filioque in the Creed, as well as other Western liturgical practices. This exchange of limited excommunications did not lead, by itself, to a formal schism between Rome and Constan*tinople, despite the views of later historians; it did, however, deepen the growing estrangement between Constantinople and Rome.
