Catholic–Eastern Orthodox relations
The Catholic Church and Eastern Orthodox Church broke communion during the East–West Schism of 1054. While an informal divide between the East and West existed prior to the split, these were internal disputes, under the umbrella of the recognised “one, holy, catholic and apostolic Church” of the Nicene Creed. It is only after the formal schism of the 11th century that two, distinct churches are seen to exist, and thus commence relations. The split has, on both sides, been immensely lamented, for it defeats the exhortation of Jesus Christ “that they may all be one". The anguish over the past has spurred both sides, particularly in recent decades, to work towards restoring Christian unity through ecumenical efforts.
Relations between the East and West have warmed over the last century, as both churches embrace a dialogue of charity. The Second Vatican Council ushered in a new era of relations for the Roman Church towards the Orthodox Church, fondly describing the Orthodox as “separated brethren” with valid sacraments and an apostolic priesthood. The Orthodox Church, on the other hand, encouraged local churches to prepare for future dialogue in the Third Pan-Orthodox Conference in Rhodes, and has since engaged in several ecumenical efforts with the Vatican. Significantly, in 1965 Pope Paul VI and Ecumenical Patriarch Athenagoras I of Constantinople jointly lifted the mutual excommunications of 1054. More recently, in November 2019, the current Patriarch of Constantinople, Patriarch Bartholomew, has stated he believes Orthodox re-union with the Catholic Church is inevitable.
Historical relations
The East and West were two centres of influence throughout Christian history. While an informal divide existed prior, in 1054 mutual excommunications were formally issued, thereby rupturing relations and causing schism. Multiple attempts at healing the union have taken place, most notably at the Second Council of Lyon and the Council of Florence, which were both ultimately unsuccessful. The only reconciliation that has been brought about is in the creation of Eastern Catholic Churches, which are also a point of disconcertment for the Eastern Orthodox.Schism and estrangement
The "Great Schism" connotes the unremitting rupture of communion between the Catholic and Orthodox families. Historians of the split have traditionally, following in the footsteps of Edward Gibbon, recognised 1054 as the watershed of relational breakdown between the Eastern and Western spheres of the Christian World. In this sense, the schism can be understood as an event; the mutual excommunications issued in 1054. The idea of a definitive break has, however, been called into question by more contemporary scholarship, which minimises the importance of this specific date.This breakdown, however, was the culmination of a process of distancing which unfolded over prior centuries. Therefore, the schism can also rightfully be understood as an ongoing process of separation between the Greek East and Latin West beginning around the year 900.
The primary cause of the schism is often recognised to be the ecclesiological differences, most notably the Bishop of Rome's growing claim to universal jurisdiction. The pre-eminence of this factor, however, is a heavily contested point; with numerous scholars placing greater importance on the theological or political disagreements instead.
It is unsurprising that the relationship immediately following the schism was one of animosity, considering Augustine diagnosed the moral origin of schism as “hatred among brothers”. The phenomenon of cultural alienation between the Latin West and Greek East is crucial for understanding the historic relationship between the Catholic and Orthodox churches. The difference was, for one, pronounced in the language of the respective spheres. As a result, communication became more strained and several seminal works were not translated on both sides.
This led to a division in theological tradition in either milieu. The Eastern theologians relied more on the work of Greek philosophy, while in the West it was the Roman system of law that permeated the minds of theologians. One of the key divergences that emerged was regarding the nature and function of the Church: fundamental ecclesiology. The relational breakdown was also highlighted by the filioque controversy, where Rome in 1014 inserted the clause “and the Son” to describe the procession of the Holy Spirit into the Nicene Creed. The Orthodox argue that this modification was made in contravention of Canon 7 of the Council of Ephesus.
Massacre of the Latins
The Massacre of the Latins was a large-scale massacre of Roman Catholics in Constantinople, the capital of the Eastern Roman Empire, by the Eastern Orthodox population of the city on April 11, 1182. The massacre was sparked by a number of factors, including the growing resentment of the Byzantines towards the Latins, who had come to dominate the empire's political and economic life, and the Byzantines' fear that the Latins were trying to undermine their Orthodox faith.The massacre began when a large mob of Byzantines attacked the Latin quarter of the city. The mob killed hundreds of Latins, including women and children, and looted and burned their homes and businesses. The massacre continued for several days, until the Byzantine authorities were able to restore order. The exact number of people killed or forced to flee during the Massacre of the Latins is unknown, but it is estimated that the bulk of the Latin community in Constantinople, which was around 60,000 people at the time, was either killed or forced to flee, according to Eustathius of Thessalonica. The Genoese and Pisan communities were especially hard hit, with some 4,000 survivors being sold into slavery to the Sultanate of Rum.
The Massacre of the Latins had a profound impact on the relationship between the Orthodox and Catholic churches. The massacre led to a hardening of attitudes on both sides, and it made it much more difficult for the two churches to reconcile their differences. The massacre also damaged the Byzantine Empire's standing in the West, and it contributed to the empire's eventual decline.
Sack of Constantinople
In April 1204, Catholic Crusader armies captured and looted Constantinople, then the capital of the Byzantine Empire and seat of the Eastern Orthodox Church. After the city's sacking, most of the Byzantine Empire's territories were divided up among the Crusaders. The sack of Constantinople was a major turning point in medieval history. The Crusaders' decision to attack the world's largest Christian city was unprecedented and immediately controversial. Reports of Crusader looting and brutality scandalised and horrified the Orthodox world; the Byzantine Empire was left much poorer, smaller, and ultimately less able to defend itself against the Seljuk and Ottoman conquests that followed; the actions of the Crusaders thus directly accelerated the collapse of Christendom in the east, and in the long run helped facilitate the later Ottoman conquest.Eight hundred years after the Fourth Crusade, Pope John Paul II twice expressed sorrow for the events of the Fourth Crusade. In 2001 he wrote that "It is tragic that the assailants, who set out to secure free access for Christians to the Holy Land, turned against their brothers in the faith. The fact that they were Latin Christians fills Catholics with deep regret." In 2004, while Bartholomew I, Patriarch of Constantinople, was visiting the Vatican, John Paul II asked, "How can we not share, at a distance of eight centuries, the pain and disgust?". In April 2004, in a speech on the 800th anniversary of the capture of the city, Ecumenical Patriarch Bartholomew I formally accepted the apology. "The spirit of reconciliation is stronger than hatred," he said during a liturgy attended by Roman Catholic Archbishop Philippe Barbarin of Lyon, France. "We receive with gratitude and respect your cordial gesture for the tragic events of the Fourth Crusade. It is a fact that a crime was committed here in the city 800 years ago."
Second Council of Lyon
The Second Council of Lyon in 1274 was an attempted reconciliation called by Pope Gregory X. The council had in attendance over 300 bishops, who discussed the union of the East and the West. Pope Gregory X said Mass for the Feast of Peter and Paul which was attended by both sides. The Greeks conceded the contested Filioque clause, which allowed reunification to be momentarily reached. However, it was only short lived, for while Emperor Michael VIII Palaeologus was enthusiastic about reunion, the Eastern clergy were largely opposed to the decisions of the council. Hence, when his son Andronikos II Palaiologos succeeded as Emperor, he repudiated the union.Council of Florence
The Council of Ferrara-Florence in 1438–1445 was the most notable historic effort towards achieving ecumenical unity. The Western Church sent letters to their Greek counterparts enthusiastic about future unity. They gathered with the intent of doctrinal agreement and ending the schism. The Greeks in attendance did eventually accept the filioque clause, as well as the Latin perspective on the Eucharist, purgatory and papal primacy.The bull of unity, Laetentur Caeli, brought about a complete reunification; having been proclaimed by the representatives of all five patriarchal sees. The evidence of unity was most sensationally seen in the participation in each other's liturgies, as well as growing appreciation for respective patristic traditions.
This was short lived, due to the Eastern Orthodox deciding to later reject the union, driven by the lower class’ anti-western sentiments and the fall of Constantinople to the Turks in 1453. Along with the antagonism was an ongoing disagreement over those theological issues dealt with in the council: the filioque, purgatory and papal primacy. The Orthodox argued that Florence should not be considered a valid Ecumenical Council, as it didn't follow the traditional method. Ultimately, Florence served to highlight the overwhelming difficulty of unification.