The document summarizes the formation of Western Europe from 800-1500 CE. It describes how Europeans embarked on the Crusades to retake Jerusalem, developed new political and economic systems, and suffered through the bubonic plague and the Hundred Years' War. The Catholic Church underwent reforms and launched the Crusades against Muslims. New architectural styles like Gothic cathedrals developed, and trade expanded, but the failure of later Crusades weakened the pope and nobility while strengthening kings.