The inclusion interpolation of the word in Filioque into the Creed is seen by Eastern Orthodox a violation of the [[canons]] of the [[Third Ecumenical Council]] in 431, which forbade and [[anathema]]tized any additions to the Creed, a prohibition which was reiterated at the [[Eighth Ecumenical Council]] in 879-880.  Any addition to the wording of the Creed is either a merely verbal modification, or a doctrinal modification. Even doctrinal modification can be validThe Eastern Orthodox, if the modification is an extension of the truth. For instancehowever, neither the word Filioque nor make no protest against the Latin phrase interpolation "Deum de Deo" ("God from God") were into the text of the Creed. The Filioque, like the phrase "Deum de Deo," was not included by neither the [[First Ecumenical Council|Council of Nicea]] , nor of [[Second Ecumenical Council|Constantinople]. However, the latter was accepted as orthodox]. The Filioque, on the other hand, violates the canons by virtue of doctrinal deviance rather than linguistic variance.  The term itself has been interpreted in both an Orthodox orthodox fashion and wrongly in a heterodox fashion. It may be is read as saying that the Spirit proceeds from the Father through (''dia'') the Son. This ; this was the position of St [[Maximus the Confessor]], among others. [citation needed] On In this reading, the Son is not an eternal cause (''aition'') of the Spirit. The heterodox reading taught , which is not held by some Roman Catholics the Latin Church, sees the Son, along with the Father, as an eternal cause of the Spirit. Most in the Eastern [[Orthodox Church]] es consider this latter reading to be a [[heresy]]. The description of the ''filioque'' as a heresy was iterated most clearly and definitively by the great [[Church Fathers|Father]] and [[Pillars of Orthodoxy|Pillar]] of the Church, St. [[Photius the Great]], in his ''On the Mystagogy of the Holy Spirit''. Some in the West held an orthodox interpretation, and some in the East held the heterodox. Photius, addressing the arguments themselves, decries the heretical [[Triadology]] which strikes at the very heart of what the Church believes about God.

In the West, St. [[Augustine of Hippo]] taught that the Spirit came from the Father ''and'' the Son, though subordinate to neither. His theology was dominant in the West until the Middle Ages. Other Latin Fathers also spoke of the Spirit proceeding from both the Father and the Son. While familiar in the West, this way of speaking was virtually unknown in the Greek-speaking, Byzantine Empire. Although the [[Second Ecumenical Council]] in 381 had expanded and completed the [[Nicene Creed]] begun at the [[First Ecumenical Council]], the [[Third Ecumenical Council]] (Ephesus, 431) had forbidden any further changes to the theology and/or wording of the Creed, except for by another [[Ecumenical Council]]. By this time, then, the text of the [[Nicene Creed]] had acquired a certain definitive authority, of ecumenical value and importance. Rome received the [[Fourth Ecumenical Council]], which referred to preceding councils, citing the authority of the text of the Creed. However, at this time, central Italy was in a state of collapse. In 410 and 455, Rome was vandalized and sacked by barbarian invasions. In 476, the Western Roman Empire fell, with the exile of Romulus Augustulus, the last emperor.

The ''filioque'' was first used in Toledo, Spain in 587 without the consultation or agreement of Although the [[Pentarchy|five patriarchsSecond Ecumenical Council]] of in 381 had expanded and completed the [[ChurchNicene Creed]] begun at that time and in direct violation of the [[canonsFirst Ecumenical Council]] of , the [[Third Ecumenical Council]] that prohibited unilateral alteration (Ephesus, 431) had forbidden any further changes to the theology of the Creed , except for by anything short of another [[Ecumenical Council]]. The purpose By this time, then, the theology of its addition in Spain was to counter a the [[heresyNicene Creed]] that was local to that regionhad acquired a certain definitive authority, probably some form of ecumenical value and importance. Rome received the [[ArianismFourth Ecumenical Council]] brought there by , which referred to preceding councils, citing the Goths (who had been missionized by authority of the Arian bishop [[Wulfila]]). The practice spread then to France where it was repudiated at theology of the Gentilly Council in 767Creed.

After generations of social upheavalThe ''filioque'' was first used in Toledo, strong leadership appeared Spain in 587 without the person consultation or agreement of Pepin the Short, king [[Pentarchy|five patriarchs]] of the Franks, [[Church]] at that time and his son, in direct violation of [[Charlemagnecanons]], crowned as emperor in 800. Charlemagne intended to restore of the Roman Empire in the West, with himself in charge, to the chagrin [[Third Ecumenical Council]] that prohibited unilateral alteration of the leaders Creed by anything short of the Eastern Roman Empireanother [[Ecumenical Council]]. These he denigrated, labelling them "Greeks" (and, by implication, not-Romans), despite the Roman capital being The purpose of its addition in the East and the continued use by Easterners of ''Roman'' Spain was to describe themselves. Charlemagne called for counter a council at Aix-la-Chapelle in 809 at which Pope [[Leo III heresy]] that was local to that region, probably some form of Rome|Leo III[[Arianism]] forbade brought there from the use of East by the ''filioque'' clause and ordered that the original version of Goths (who had been missionized by the Arian bishop [[Nicene-Constantinopolitan CreedWulfila]] be engraved on silver tablets displayed ). The practice spread then to France where it was repudiated at St. Peter's Basilica in Rome, apparently so that his conclusion would not be overturned the Gentilly Council in the future767.

Some historians have suggested that After generations of social upheaval, strong leadership appeared in the person of Pepin the Short, king of the Franks , and his son, [[Charlemagne]], crowned as emperor in 800. Charlemagne intended to restore the Roman Empire in the 9th century pressured West, with himself in charge, to the chagrin of the leaders of the Byzantine Empire. Charlemagne called for a council at Aix-la-Chapelle in 809 at which Pope to adopt [[Leo III of Rome|Leo III]] forbade the use of the ''filioque'' in order to drive a wedge between clause and ordered that the Roman Church and original version of the other patriarchates[[Nicene-Constantinopolitan Creed]] be engraved on silver tablets displayed at St. Peter's Basilica in Rome. Despite this action, the ''filioque'' had come came into wide use in the West and became widely thought to be an integral part of the Creed, while Rome, renowned for its stability and conservatism, resisted. Similarly, unleavened bread had come to be thought of as normative for the [[Eucharist]]; diocesan priests were expected to be unmarried. In such cases, in the West, ancient tradition was forgotten. Contemporary usage was thought to be normative and authentic. In these matters of discipline, the influence of the Franks is certain. They intended to exalt Charlemagne, as the new Roman Emperor. The Catholic religion, as they knew it, was to be part of the package. Meanwhile, from c. 726 to 843, the Eastern Roman Byzantine Empire, under the thumb of successive emperors, was dominated by the heresy of [[iconoclasm]]. Both Franks and Greeks, in their own way, departed from ancient tradition. Unlike the East, however, where iconoclasm was repudiated at the [[Seventh Ecumenical Council]] and the use of icons later confirmed by the [[Theodora (9th century empress)|Empress Theodora]], the West to date never recovered from its departure.

Within a couple of generations, in 858, a new situation came to pass. The Eastern Byzantine Emperor Michael III removed [[Ignatius of Constantinople|Ignatius I]] as patriarch of Constantinople. The emperor replaced him with a layman, St. [[Photius the Great]], who was the first Imperial Secretary and Imperial Ambassador to Baghdad. However, Ignatius refused to bow to secular authority. Michael and Photius invited Pope [[Nicholas I of Rome]] to send legates to preside over a synod in Constantinople to settle the matter. With the council, the legates confirmed the patriarchate of Photius, much to Nicholas's chagrin, who then declared that they had "exceeded their authority."

In opposition to this removal of Ignatius, the bishop of Rome supported Ignatius as legitimate patriarch. Moreover, in violation to violating existing canons, Photius had been ordained to the office of bishop very quickly. Some scholarship suggests that violation of these canons was the main reason the bishop of Rome rejected the appointment of Photius, though other major actions by Nicholas to bolster his power and position as pope puts his intervention in Eastern ecclesiastical matters more firmly in the context of his general programme of the growth of papal monarchy.

Therefore, after After the arrival of an embassy from Ignatius, in 862, Nicholas said that Photius was deposed, as well as the bishop who ordained him and all the clergy Photius had appointed. The sheer temerity of this action did not even generate a response from Constantinople. However, several years later in 867, Photius finally rejected the Pope's assertion, particularly because of the activities of Latin missionaries in Bulgaria, who were, as St. Photius saysclaimed, turning the Orthodox Christians there away from their pure the faith and leading them into [[heresy]]—most notably, the ''filioque''. Photius' response cited the ''filioque'' as proof that Rome had a habit of overstepping its proper limits.

In 867 and 869-70, synods in Rome and Constantinople (the [[Robber Council of 869-870]]) restored Ignatius to his position as patriarch and deposed Photius. In 877, after the death of Ignatius, Photius again resumed office, by order of the emperor and by the request of Ignatius himself, to whom Photius had been reconciled. In 879-880, he was officially restored to his see and the ''filioque'' effectively condemned by the [[Eighth Ecumenical Council]], a council at which papal legates participated and which the current pope, [[John VIII of Rome|John VIII]], eventually confirmed. He was deposed in 886 when Leo VI took over as emperor, who had had a dispute with his father and turned his animosity for his father toward one of his father's friends, Photius. Photius spent the rest of his life as a monk in exile in Armenia; he is revered by the Eastern Orthodox today as a [[saint]], one of the great [[Pillars of Orthodoxy]]. He was the first important [[theologian]] to accuse Rome of [[heresy]] in the matter of the ''filioque,''although it was an accusation based on a false reading of the Latin understanding.

===Rome capitulates to Filioquist pressureaccepts Filioque as valid in Latin===

Later, in 1014, the German Emperor Henry II of the Holy Roman Empire visited Rome for his coronation and found that the Creed was not used during the Mass. At his request, the bishop of Rome added the Creed, as it was known in the West with the ''filioque'', after the Gospel. This was the first time the Creed in the [[Mass]] at Rome.

In 1054, however, the argument contributed to the [[Great Schism]] of the East and West, and the West went so far as to accuse the East of heresy for not accepting the theology of the ''filioque''. There were many other issues involved, in large part based on misunderstandings between Greek and Latin traditions. In addition to the actual difference in wording and doctrine in the ''filioque'', a related issue was the right of the Pope to make a change in the [[Nicene-Constantinopolitan Creed]] on his own for exclusive use in the Roman liturgy, apart from an [[Ecumenical Council]].

In the thirteenth century, Roman saint [[St. Thomas Aquinas]] was one of the dominant Scholastic theologians. He dealt explicitly with the processions of the divine Persons in his ''Summa Theologica''. While the theology of Aquinas and other Scholastics was dominant in the Western Middle Ages, for all its apparent clarity and brilliance, it remains theology, not official [[Roman Catholic Church]] teaching.

In 1274, the Second [[Council of Lyons]] said that the [[Holy Spirit]] proceeds from the [[God the Father|Father]] and the [[Christ|Son]], in accord with the ''filioque'' in the contemporary Latin version of the [[Nicene Creed]]. Reconciliation with the East, through this council, did not last. Remembering the Crusaders' sack of Constantinople in 1204, Eastern Orthodox Christians did not want to be reconciled with the West in terms of capitulation to Latin [[Triadology]] and [[ecclesiology]]. In 1283, Patriarch [[John Beccus]], who supported reconciliation with the Latin Church, was forced to abdicate; reunion failed.

The Crusaders in question were the Venetians of the [[Fourth Crusade]], who had earlier been excommunicated for attacking other Christians. In 1204, they were getting avenging the slaughter of Venetian merchants, in rioting, that took place in 1182. Pope Innocent III had sent them a letter, asking them not to attack Constantinople; after hearing of the sack of the city, he lamented their action and disowned them. Nevertheless, the people of Constantinople had a deep hatred for the people they called the "Latins" or the "Franks," and even though the sack of course the Western church's major "endowment" from Constantinople was done against the spoils carried away now still largely rests in the hands will of the VaticanPope.

For much of the 14th century, there were two bishops, each claiming to be Pope, each excommunicating the followers of the other. The Great Western Schism concluded with yet a third individual claiming to be Pope and the Council of Constance. The East could hardly seek reconciliation with a Western Church divided against itself. (In the middle of the century, about a third of Western Europe died of the Black Death with no help from the East.)

At the [[Council of Florence]] in 1439, Emperor [[John VIII Palaeologus]], Patriarch Joseph of Constantinople, and other bishops from the East travelled to northern Italy in hope of reconciliation with the West, mainly in order to solicit military assistance to fend off the encroaching Turkish invaders. After extensive discussion, in Ferrara, and then in Florence, they acknowledged that some Latin Fathers spoke of the procession of the Spirit differently from the Greek Fathers. Since the general consensus of the Fathers was held to be reliable, as a witness to common faith, the Western usage was held not to be a heresy and not a barrier to restoration of full communion. All the Eastern patriarchs and bishops present, but one, agreed and except [[Mark of Ephesus]] signed a decree of union between East and West, ''Laetentur Coeli'' in 1439. The one bishop who refused to sign and was later heralded as a Pillar of Orthodoxy by the Church was St. [[Mark of Ephesus]], who followed in the footsteps of the previous Pillar of Orthodoxy, St. [[Photius the Great]].

Officially and publicly, the Roman churches Catholic and the Eastern Orthodox churches Churches were back in communion. However, the reconciliation achieved at Florence was soon destroyed, founded as it was on a compromise of faith. Numerous Eastern Orthodox faithful and bishops rejected the union, saying that the even though it was decided by an ecumenical council's teachings were incorrect and therefore not ecumenical. Moreover, after the Turks [[Fall of Constantinople|conquered Constantinople in 1453]], they fostered separation from the West, which remained an adversary to Islamic political and military dominance. Furthermore, the patriarch, Gennadius, was also one of the bishops who had repudiated the reunion of Florence on his own initiative.

Undeniably, the ''filioque'' controversy was at least officially resolved, for both Eastern Orthodox and Catholic Christians. However, because of the historical situation and because of the different ecclesiologies of the East and West, this resolution was neither fully received nor permanently sustained.

In December of 1452, a reunion [[Divine Liturgy|liturgy]] was held at [[Hagia Sophia (Constantinople)|Hagia Sophia]] in Constantinople at which the Pope's name was commemorated and the ''filioque'' used in the Creed; some clergy and laity boycotted it. On the evening of [[May 28]], 1453, however, another liturgy was held which also commemorated the Pope and used the ''filioque'', which was not boycotted.

In the judgment of the consultation, the question of the ''filioque'' is no longer a "Church-dividing" issue, one which would impede full reconciliation and full communion, once again. It still stands for the bishops and faithful of the Roman Catholic and Eastern Orthodox Churches to review this work and to make whatever decisions would be appropriate.

There has never been a specific conciliar statement in the Eastern [[Orthodox Church]]es that defined the ''filioque'' as [[heresy]]. That being said, however, it has been regarded as heretical by multiple Orthodox saints, including Ss. [[Photius the Great]], [[Mark of Ephesus]], and [[Gregory Palamas]] (the three Pillars of Orthodoxy). At the [[Third Ecumenical Council]] and the [[Eighth Ecumenical Council|"Photian" council of 879-880]] (both of which Rome ratified), all changes to the theology of the Creed are anathematized. It was explicitly denounced as heretical by the non-ecumenical, 1848 ''[[Encyclical of the Eastern Patriarchs]]''.