<P> With the coronation of Charlemagne by Pope Leo III in 800, his new title as Patricius Romanorum, and the handing over of the keys to the Tomb of Saint Peter, the papacy had acquired a new protector in the West . This freed the pontiffs to some degree from the power of the emperor in Constantinople but also led to a schism, because the emperors and patriarchs of Constantinople interpreted themselves as the true descendants of the Roman Empire dating back to the beginnings of the Church . Pope Nicholas I had refused to recognize Patriarch Photios I of Constantinople, who in turn had attacked the pope as a heretic, because he kept the filioque in the creed, which referred to the Holy Spirit emanating from God the Father and the Son . The papacy was strengthened through this new alliance, which in the long term created a new problem for the Popes, when in the Investiture Controversy succeeding emperors sought to appoint bishops and even future popes . After the disintegration of the Carolingian Empire and repeated incursions of Islamic forces into Italy, the papacy, without any protection, entered a phase of major weakness . </P> <P> The Cluniac reform of monasteries that began in 910 placed abbots under the direct control of the pope rather than the secular control of feudal lords, thus eliminating a major source of corruption . This sparked a great monastic renewal . Monasteries, convents and cathedrals still operated virtually all schools and libraries, and often functioned as credit establishments promoting economic growth . After 1100, some older cathedral schools split into lower grammar schools and higher schools for advanced learning . First in Bologna, then at Paris and Oxford, many of these higher schools developed into universities and became the direct ancestors of modern Western institutions of learning . It was here where notable theologians worked to explain the connection between human experience and faith . The most notable of these theologians, Thomas Aquinas, produced Summa Theologica, a key intellectual achievement in its synthesis of Aristotelian thought and the Gospel . Monastic contributions to western society included the teaching of metallurgy, the introduction of new crops, the invention of musical notation and the creation and preservation of literature . </P> <P> During the 11th century, the East--West schism permanently divided Christianity . It arose over a dispute on whether Constantinople or Rome held jurisdiction over the church in Sicily and led to mutual excommunications in 1054 . The Western (Latin) branch of Christianity has since become known as the Catholic Church, while the Eastern (Greek) branch became known as the Orthodox Church . The Second Council of Lyon (1274) and the Council of Florence (1439) both failed to heal the schism . Some Eastern churches have since reunited with the Catholic Church, and others claim never to have been out of communion with the pope . Officially, the two churches remain in schism, although excommunications were mutually lifted in 1965 . </P> <P> The 11th century saw the Investiture Controversy between Emperor and Pope over the right to make church appointments, the first major phase of the struggle between Church and state in medieval Europe . The Papacy were the initial victors, but as Italians divided between Guelphs and Ghibellines in factions that were often passed down through families or states until the end of the Middle Ages, the dispute gradually weakened the Papacy, not least by drawing it into politics . The Church also attempted to control, or exact a price for, most marriages among the great by prohibiting, in 1059, marriages involving consanguinity (blood kin) and affinity (kin by marriage) to the seventh degree of relationship . Under these rules, almost all great marriages required a dispensation . The rules were relaxed to the fourth degree in 1215 (now only the first degree is prohibited by the Church - a man cannot marry his stepdaughter, for example). </P>

When did the catholic church become the catholic church
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