在東西教會分裂後，新成立的中歐王國波蘭、匈牙利和波西米亞等紛紛皈依西方基督教。羅馬天主教會發展成為強權之一，導致教皇與羅馬皇帝之間産生衝突。公元1129年羅馬天主教會建立宗教裁判所，用強製手段保證西歐人信奉羅馬天主教。宗教裁判所裁判異端（異教徒）令其懺悔。如其不從便判死刑。在此期間許多領主與貴族統轄教會。剋呂尼的僧侶努力建立一所沒有領主和貴族的教會，並獲成功。教皇額我略七世繼承了僧侶們的事業，並訂下兩個目標：擺脫國王和貴族的控製，與增強教皇的權力。羅馬天主教會的教區由於異教王國（斯堪的納維亞、立陶宛、波蘭、匈牙利）的歸正，基督教收復安達盧西亞失地與十字軍東徵迅速擴大。到15世紀歐洲大部分地區已經皈依羅馬天主教。
早期的文明復興跡象在11世紀的西歐就已開始顯現，意大利重新開始進行貿易，使得諸如威尼斯和佛羅倫薩這樣的城邦的經濟和文化得以發展。同時，民族國傢開始在法國、英格蘭、西班牙和葡萄牙形成，雖然它們的形成過程（通常以君主、貴族封建領主和教會的對峙為標志）長達幾個世紀。這些新的民族國傢開始使用自己的文化語言代替傳統的拉丁語。這一運動的主要人物包括但丁·亞利基利與皮桑夫人，前者以意大利語著書，後者雖然是意大利（威尼斯）人但移居法國以法語寫作。另一方面，實際位於德國和意大利的神聖羅馬帝國，進一步分裂成大量封建公國和小城邦，它們對帝國的服從衹是形式上的。
蒙古帝國興起後的13與14世紀經常被稱為“蒙古時期”。蒙古軍隊在拔都率領下嚮西方擴張。被他們徵服的西方國傢包括俄羅斯全境（除了諾夫哥羅德成為附庸以外）、欽察地區、匈牙利和波蘭（仍然保留主權國傢地位）。蒙古的記載顯示在由於窩闊臺之死被蒙古召回之前，拔都計劃完全徵服所有的歐洲諸國，以對奧地利、意大利和德國的鼕季攻勢為起點。很多歷史學家相信僅僅由於窩闊臺的死製止了歐洲被完全徵服。在俄國，金帳汗國的蒙古人統治持續了近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.