After the East-West Schism, conventionally dated to 1054, a brief reunification was agreed to between the Pope and a number of Eastern Orthodox bishops at the Council of Florence.

* 1965 – Pope Paul VI and Patriarch Athenagoras simultaneously revoke mutual excommunications that had been in place since 1054.

* 1999 – Pope John Paul II travels to Romania becoming the first pope to visit a predominantly Eastern Orthodox country since the Great Schism in 1054.

The two were married in 1053 or 1054 in the church of San Pietro at Mantua by Pope Leo IX himself as he returned from a trip to Germany.

Pope Leo IX ( in office 1049 to 1054 ) also had family ties to the dynasty, since his grandfather Hugo III was the brother of Adelheid, the grandmother of Henry III.

* June 21 – Pope Leo IX ( d. 1054 )

His meeting with Pope Paul VI in 1964 in Jerusalem led to rescinding the excommunications of 1054 which historically mark the Great Schism, the schism between the churches of the East and West.

The controversial declaration did not end the 1054 schism, but rather showed a desire for greater reconciliation between the two churches, as represented by Pope Paul VI and Ecumenical Patriarch Athenagoras I.

Pope Saint Leo IX ( 21 June 1002 – 19 April 1054 ), born Bruno of Egisheim-Dagsburg, was Pope from 12 February 1049 to his death.

From June 1053 to March 1054 the Pope was nevertheless held hostage at Benevento, in honourable captivity, until he acknowledged the Normans conquests in Calabria and Apulia.

Thomas Asbridge argues that the First Crusade was Pope Urban II's attempt to expand the power of the church, and reunite the churches of Rome and Constantinople, which had been in schism since 1054.

" To the former belong the mutual revocation in 1965 of the anathemas of 1054 ( see below Contemporary developments ), returning the relics of Sabbas the Sanctified ( a common saint ) to Mar Saba in the same year, and the first visit of a Pope to an Orthodox country in a millennium ( Pope John Paul II accepting the invitation of the Patriarch of the Romanian Orthodox Church, Teoctist, in 1999 ), among others.

The first pope to invoke it was Pope Leo IX, in a letter sent in 1054 to Michael I Cerularius, Patriarch of Constantinople.

In 1054, the Great Schism split Christianity into the Eastern Orthodox Church-which consisted of the four Orthodox Christian Patriarchs of Antioch, Jerusalem, Constantinople and Alexandria-under the jurisdiction of Constantinople and the Roman Catholic Church-which consisted of the Pope of Rome.

The addition of " and the Son " was ( along with the Papal supremacy and some other questions ) one of the causes for the East – West Schism formalized in 1054 by simultaneous proclamations of " Anathema " by the Bishop of Rome ( Pope ) in the West and the leadership of the Orthodox Churches ( Patriarch ) in the East.

In 1965, the Pope Paul VI and the Ecumenical Patriarch of Constantinople Athenagoras I nullified the anathemas of 1054, although this nullification of measures taken against a few individuals was essentially a goodwill gesture and did not constitute any sort of reunion between churches.

When Pope Leo died on 19 April 1054, the legates ' authority legally ceased, but they effectively ignored this technicality.

The first pope to use it was Pope Leo IX in a letter sent in 1054 to Michael I Cerularius, Patriarch of Constantinople, in which he cited a large portion of the document, believing it genuine.

When the Great Schism took place in 1054, the four Greek Patriarchs of Antioch, Jerusalem, Constantinople and Alexandria " formed " the Eastern Orthodox Church, while the Pope of Rome " formed " the Roman Catholic Church.

As they were paid with lands, soon they were powerful enough to challenge Papal authority ; in 1054, they defeated the Pope at the Battle of Civitate, forcing him to acknowledge their authority.

Though normally dated to 1054, when Pope Leo IX and Patriarch of Constantinople Michael I Cerularius excommunicated each other, the East-West Schism was actually the result of an extended period of estrangement between the two Churches.

Bernold of Constance ( c. 1054 – Schaffhausen, September 16, 1100 ) was a chronicler and writer of tracts, and a defender of the Church reforms of Pope Gregory VII.

Leo IX sent a letter to Michael Cærularius, Patriarch of Constantinople, in 1054, that cited a large portion of the Donation of Constantine, believing it genuine.

:" The first pope who used it in an official act and relied upon it, was Leo IX ; in a letter of 1054 to Michael Cærularius, Patriarch of Constantinople, he cites the " Donatio " to show that the Holy See possessed both an earthly and a heavenly imperium, the royal priesthood.

The first pope who used it in an official act and relied upon, Leo IX, cites the " Donatio " in a letter of 1054 to Michael Cærularius, Patriarch of Constantinople, to show that the Holy See possessed both an earthly and a heavenly imperium, the royal priesthood.

:" The first pope who used it in an official act and relied upon it was Leo IX ; in a letter of 1054 to Michael Cærularius, Patriarch of Constantinople, he cites the " Donatio " to show that the Holy See possessed both an earthly and a heavenly imperium, the royal priesthood.

* Pope Leo IX ( 1049 – 1054 )

The text, from Saint Paul's church — no longer existent — in the Flemish town of Oudenberg, describes the death of Pope Leo IX in Spring 1054.

The Greek and Latin texts of the Schism was studied by Michele Giuseppe D ' Agostino, Il Primato della Sede di Roma in Leone IX ( 1049 – 1054 ).

In 1054 King Edward sent Ealdred to Germany to obtain Emperor Henry III's help in returning Edward the Exile, son of Edmund Ironside, to England.

In 1054 Edward sent Siward to invade Scotland.

It is far from certain that Eógan died at Carham, and it is reasonably certain that there were kings of Strathclyde as late as the 1054, when Edward the Confessor sent Earl Siward to install " Máel Coluim son of the king of the Cumbrians ".

It is the church in which Cardinal Humbert in 1054 excommunicated Michael I Cerularius – which is commonly considered the start of the Great Schism.

Humbert, Frederick of Lorraine, and Peter, Archbishop of Amalfi, arrived in April 1054 and were met with a hostile reception ; they stormed out of the palace, leaving the papal response with Michael, who in turn was even more angered by their actions.

The former was the abbey of Cardinal Humbert of Silva Candida, who excommunicated the patriarch of Constantinople, Michael I Cerularius, in 1054, thus precipitating the Great Schism, and the latter was his own final resting place.

In 1054, Patriarch Michael Kerularios and Cardinal Humbert of Silva Candida had excommunicated each other, thus formalizing a schism that had been developing for many years.

Constantine's foundation gave prestige to the Bishop of Constantinople, who eventually came to be known as the Ecumenical Patriarch, a situation that contributed to the Great Schism that divided Western Catholicism from Eastern Orthodoxy from 1054 onwards.

* A Protest to Patriarch Athenagoras On the Lifting of the Anathemas of 1054 by Metr.

The Patriarch rejected the claims of papal primacy, and subsequently the One Church was split in two in the Great East – West Schism of 1054.

For example, according to Byzantinist Anthony Kaldellis, " In 1054 he was accused by his erstwhile friend, the future Patriarch John Xiphilinos, of forsaking Christ to follow Plato.

Before the East-West Schism in 1054, the Christian Church within the borders of the ancient Roman Empire was effectively ruled by five patriarchs ( the " Pentarchy "): the Bishop of Rome ( who rarely used the title " Patriarch ") and those of Constantinople, Jerusalem, Alexandria, and Antioch.

The schism is conventionally dated to 1054, when the Patriarch of Constantinople and the Papal Legate Humbert of Mourmoutiers issued mutual excommunications that have since been revoked.

He played a role in the process leading to the Schism of 1054 by rejecting a proposal by Patriarch Eustathius of Constantinople to recognise that Patriarchate's sphere of interest in the east.

In 1054, Roman legates traveled to Cerularius to deny him the title Ecumenical Patriarch and to insist that he recognize the Church of Rome's claim to be the head and mother of the churches.