On the death of
Pope Damasus II in 1048, Bruno was selected as his successor by an assembly at
Worms in December. Both the emperor and the Roman delegates concurred. However, Bruno apparently favoured a
canonical election and stipulated as a condition of his acceptance that he should first proceed to Rome and be freely elected by the voice of the clergy and people of Rome. Setting out shortly after Christmas, he met with abbot
Hugh of Cluny at
Besançon, where he was joined by the young monk Hildebrand, who afterwards became
Pope Gregory VII; arriving in pilgrim garb at Rome in the following February, he was received with much cordiality, and at his consecration assumed the name Leo IX.
Theology Leo IX favoured celibacy for the clergy in his reformation of the Catholic Church. One of his first public acts was to hold the well-known Easter synod of 1049, at which celibacy of the clergy (down to the rank of
subdeacon) was required anew. Also, the Easter synod was where the pope at least succeeded in making clear his own convictions against every kind of
simony. The greater part of the year that followed was occupied by one of those progresses through Italy, Germany and France which form a marked feature in Leo IX's pontificate. After presiding over a synod at
Pavia, he joined Henry III in Saxony and accompanied him to
Cologne and
Aachen. He also summoned a meeting of the higher clergy in
Reims in which several important reforming decrees were passed. At
Mainz, he held a council at which the Italian and French as well as the German clergy were represented, and ambassadors of the Byzantine emperor were present. Here too, simony and the marriage of the clergy were the principal matters dealt with. After his return to Rome, Leo held another
Easter synod on 29 April 1050. It was occupied largely with the controversy about the teachings of
Berengar of Tours. In the same year he presided over provincial synods at
Salerno,
Siponto and
Vercelli, and in September revisited his native Germany, returning to Rome in time for a third Easter synod at which the question of the
reordination of those who had been ordained by simonists was considered. In 1052, he joined the emperor at
Pressburg and vainly sought to secure the submission of the
Hungarians. At
Regensburg,
Bamberg and
Worms, the papal presence was celebrated with various ecclesiastical solemnities. In early 1053, Leo arbitrated a dispute between the
archbishop of Carthage and the bishop of
Gummi over ecclesiastical precedence.
Relations with Constantinople Patriarch
Michael I Cerularius of Constantinople, through
Leo of Ohrid, Archbishop of Bulgaria, wrote to the pope denouncing the use of unleavened bread and fasting days in the Latin Church. Leo IX sent a letter to Michael I in 1054, citing a large portion of the
Donation of Constantine, believing it was genuine. Leo assured Michael that the donation was completely genuine, not a fable, so only the apostolic successor to Peter possessed that primacy and was the rightful head of all the Church. Before his death, Leo IX had sent a legatine mission under Cardinal
Humbert of Silva Candida to Constantinople to negotiate with Patriarch Michael Cerularius in response to his actions concerning the Church in Constantinople. Humbert quickly disposed of negotiations by delivering a bull excommunicating the Patriarch. Despite this, the break began the Great
East–West Schism.
Conflict with the Normans In constant fear of attack from the
Normans in the south of Italy, the
Byzantines turned in desperation to the Normans' own spiritual chief, Pope Leo IX, and, according to
William of Apulia, begged him "to liberate Italy that now lacks its freedom and to force that wicked people, who are pressing
Apulia under their yoke, to leave". After a fourth Easter synod in 1053, Leo IX set out against the
Norman in the south with an army of Italians and
Swabian
mercenaries. "As fervent Christians the Normans were reluctant to fight their spiritual leader and tried to sue for peace but the Swabians mocked them—battle was inevitable." Leo IX led the army himself, but his forces suffered total defeat at the
Battle of Civitate on 15 June 1053. Nonetheless, on going out from the city to meet the victorious enemy, he was received with every token of submission, pleas for forgiveness and oaths of fidelity and homage. From June 1053 to March 1054, the pope was nevertheless held hostage at
Benevento, in honourable captivity, until he acknowledged the Norman conquests in
Calabria and Apulia. He did not long survive his return to Rome, where he died on 19 April 1054. == Selected works ==