在东西教会分裂后，新成立的中欧王国波兰、匈牙利和波西米亚等纷纷皈依西方基督教。罗马天主教会发展成为强权之一，导致教皇与罗马皇帝之间产生冲突。公元1129年罗马天主教会建立宗教裁判所，用强制手段保证西欧人信奉罗马天主教。宗教裁判所裁判异端（异教徒）令其忏悔。如其不从便判死刑。在此期间许多领主与贵族统辖教会。克吕尼的僧侣努力建立一所没有领主和贵族的教会，并获成功。教皇额我略七世继承了僧侣们的事业，并订下两个目标：摆脱国王和贵族的控制，与增强教皇的权力。罗马天主教会的教区由于异教王国（斯堪的纳维亚、立陶宛、波兰、匈牙利）的归正，基督教收复安达卢西亚失地与十字军东征迅速扩大。到15世纪欧洲大部分地区已经皈依罗马天主教。
早期的文明复兴迹象在11世纪的西欧就已开始显现，意大利重新开始进行贸易，使得诸如威尼斯和佛罗伦萨这样的城邦的经济和文化得以发展。同时，民族国家开始在法国、英格兰、西班牙和葡萄牙形成，虽然它们的形成过程（通常以君主、贵族封建领主和教会的对峙为标志）长达几个世纪。这些新的民族国家开始使用自己的文化语言代替传统的拉丁语。这一运动的主要人物包括但丁·亚利基利与皮桑夫人，前者以意大利语著书，后者虽然是意大利（威尼斯）人但移居法国以法语写作。另一方面，实际位于德国和意大利的神圣罗马帝国，进一步分裂成大量封建公国和小城邦，它们对帝国的服从只是形式上的。
蒙古帝国兴起后的13与14世纪经常被称为“蒙古时期”。蒙古军队在拔都率领下向西方扩张。被他们征服的西方国家包括俄罗斯全境（除了诺夫哥罗德成为附庸以外）、钦察地区、匈牙利和波兰（仍然保留主权国家地位）。蒙古的记载显示在由于窝阔台之死被蒙古召回之前，拔都计划完全征服所有的欧洲诸国，以对奥地利、意大利和德国的冬季攻势为起点。很多历史学家相信仅仅由于窝阔台的死制止了欧洲被完全征服。在俄国，金帐汗国的蒙古人统治持续了近250年。
After the East-West Schism, Western Christianity was adopted by newly created kingdoms of Central Europe: Poland, Hungary and Bohemia. The Roman Catholic Church developed as a major power, leading to conflicts between the Pope and Emperor. In 1129 AD the Roman Catholic Church established the Inquisition to make Western Europeans Roman Catholic by force. The Inquisition punished those who practised heresy (heretics) to make them repent. If they could not do so, the penalty was death. During this time many Lords and Nobles ruled the church. The Monks of Cluny worked hard to establish a church where there were no Lords or Nobles ruling it. They succeeded. Pope Gregory VII continued the work of the monks with 2 main goals, to rid the church of control by kings and nobles and to increase the power of the pope. The area of the Roman Catholic Church expanded enormously due to conversions of pagan kings (Scandinavia, Lithuania, Poland, Hungary), Christian reconquista of Al-Andalus, and crusades. Most of Europe was Roman Catholic in the 15th century.
Early signs of the rebirth of civilization in western Europe began to appear in the 11th century as trade started again in Italy, leading to the economic and cultural growth of independent city states such as Venice and Florence; at the same time, nation-states began to take form in places such as France, England, Spain, and Portugal, although the process of their formation (usually marked by rivalry between the monarchy, the aristocratic feudal lords and the church) actually took several centuries. These new nation-states began writing in their own cultural vernaculars, instead of the traditional Latin. Notable figures of this movement would include Dante Alighieri and Christine de Pisan (born Christina da Pizzano), the former writing in Italian, and the latter although an Italian (Venice) relocated to France and wrote in French.(See Reconquista for the latter two countries.) On the other hand, the Holy Roman Empire, essentially based in Germany and Italy, further fragmented into a myriad of feudal principalities or small city states, whose subjection to the emperor was only formal.
The 13th and 14th century, when the Mongol Empire came to power, is often called the Age of the Mongols. Mongol armies expanded westward under the command of Batu Khan. Their western conquests included almost all of Russia (save Novgorod, which became a vassal), Kipchak lands, Hungary, and Poland (Which had remained sovereign state). Mongolian records indicate that Batu Khan was planning a complete conquest of the remaining European powers, beginning with a winter attack on Austria, Italy and Germany, when he was recalled to Mongolia upon the death of Great Khan Ögedei. Most historians believe only his death prevented the complete conquest of Europe. In Russia, the Mongols of the Golden Horde ruled for almost 250 years.