throughout Europe. Ordinary people also trekked vast distances on pilgrimages to express their piety and pray at the site of holy relics. Monumental abbeys and cathedrals were constructed and decorated with sculptures, hangings, mosaics and works belonging to one of the greatest epochs of art and providing stark contrast to the monotonous and cramped conditions of ordinary living. Abbot Suger of the Abbey of St. Denis is considered an influential early patron of Gothic architecture and believed that love of beauty brought people closer to God: "The dull mind rises to truth through that which is material". Clark calls this "the intellectual background of all the sublime works of art of the next century and in fact has remained the basis of our belief of the value of art until today". By the year 1000 feudalism had become the dominant social, economic and political system. At the top of society was the monarch, who gave land to nobles in exchange for loyalty. The nobles gave land to vassals, who served as knights to defend their monarch or noble. Under the vassals were the peasants or serfs. The feudal system thrived as long as peasants needed protection by the nobility from invasions originating inside and outside of Europe. So as the 11th century progressed, the feudal system declined along with the threat of invasion. In 1054, after centuries of strained relations, the Great Schism occurred over differences in doctrine, splitting the Christian world between the Catholic Church, centered in Rome and dominant in the West, and the Orthodox Church, centered in Constantinople, capital of the Byzantine Empire. The last pagan land in Europe was converted to Christianity with the conversion of the Baltic peoples in the High Middle Ages, bringing them into Western civilization as well. As the Medieval period progressed, the aristocratic military ideal of Chivalry and institution of knighthood based around courtesy and service to others became culturally important. Large Gothic cathedrals of extraordinary artistic and architectural intricacy were constructed throughout Europe, including Canterbury Cathedral in England, Cologne Cathedral in Germany and Chartres Cathedral in France (called the "epitome of the first great awakening in European civilisation" by Kenneth Clark). The period produced ever more extravagant art and architecture, but also the virtuous simplicity of such as St Francis of Assisi (expressed in the Prayer of St Francis) and the epic poetry of Dante Alighieri's Divine Comedy. As the