section_path: Middle Ages/High Middle Ages
section_name: High Middle Ages
paragraph_text: High Middle Ages
  
  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.
  
  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.
  
  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).
  
  Pope Urban II launched the First Crusade in 1095 when he received an appeal from Byzantine emperor Alexius I to help ward off a Turkish invasion. Urban further believed that a Crusade might help bring about reconciliation with Eastern Christianity. Fueled by reports of Muslim atrocities against Christians, the series of military campaigns known as the Crusades began in 1096. They were intended to return the Holy Land to Christian control. The goal was not permanently realized, and episodes of brutality committed by the armies of both sides left a legacy of mutual distrust between Muslims and Western and Eastern Christians. The sack of Constantinople during the Fourth Crusade left Eastern Christians embittered, despite the fact that Pope Innocent III had expressly forbidden any such attack. In 2001, Pope John Paul II apologized to the Orthodox Christians for the sins of Catholics including the sacking of Constantinople in 1204.
  
  Two new orders of architecture emerged from the Church of this era. The earlier Romanesque style combined massive walls, rounded arches and ceilings of masonry. To compensate for the absence of large windows, interiors were brightly painted with scenes from the Bible and the lives of the saints. Later, the Basilique Saint-Denis marked a new trend in cathedral building when it utilized Gothic architecture. This style, with its large windows and high, pointed arches, improved lighting and geometric harmony in a manner that was intended to direct the worshiper's mind to God who "orders all things". In other developments, the 12th century saw the founding of eight new monastic orders, many of them functioning as Military Knights of the Crusades. Cistercian monk Bernard of Clairvaux exerted great influence over the new orders and produced reforms to ensure purity of purpose. His influence led Pope Alexander III to begin reforms that would lead to the establishment of canon law. In the following century, new mendicant orders were founded by Francis of Assisi and Dominic de Guzmán which brought consecrated religious life into urban settings.
  
  12th-century France witnessed the growth of Catharism in Languedoc. It was in connection with the struggle against this heresy that the Inquisition originated. After the Cathars were accused of murdering a papal legate in 1208, Pope Innocent III declared the Albigensian Crusade. Abuses committed during the crusade caused Innocent III to informally institute the first papal inquisition to prevent future massacres and root out the remaining Cathars. Formalized under Gregory IX, this Medieval inquisition executed an average of three people per year for heresy at its height. Over time, other inquisitions were launched by the Church or secular rulers to prosecute heretics, to respond to the threat of Moorish invasion or for political purposes. The accused were encouraged to recant their heresy and those who did not could be punished by penance, fines, imprisonment or execution by burning.
  
  A growing sense of church-state conflicts marked the 14th century. To escape instability in Rome, Clement V in 1309 became the first of seven popes to reside in the fortified city of Avignon in southern France during a period known as the Avignon Papacy. The papacy returned to Rome in 1378 at the urging of Catherine of Siena and others who felt the See of Peter should be in the Roman church. With the death of Pope Gregory XI later that year, the papal election was disputed between supporters of Italian and French-backed candidates leading to the Western Schism. For 38 years, separate claimants to the papal throne sat in Rome and Avignon. Efforts at resolution further complicated the issue when a third compromise pope was elected in 1409. The matter was finally resolved in 1417 at the Council of Constance where the cardinals called upon all three claimants to the papal throne to resign, and held a new election naming Martin V pope.