Invasions by Vikings, Magyars, and Muslims, along with civil wars, created instability in the ninth and tenth centuries. Local nobles became the strongest powers against external threats, establishing a form of decentralized government later known as feudalism. By the twelfth century rulers in some parts of Europe had reasserted authority and were beginning to develop new institutions of government and legal codes that enabled them to assert power over lesser lords and the general population. The papacy also consolidated its power, though these moves were sometimes challenged by kings and emperors. Monasteries continued to be important places for learning and devotion, and new religious orders were founded. A papal call to retake the holy city of Jerusalem led to the Crusades.

The vast majority of medieval Europeans were peasants who lived in small villages and worked their own and their lord’s land. Nobles were a tiny fraction of the total population, but they exerted great power over all aspects of life. Medieval towns and cities grew initially as trading centers and then became centers of production.

Towns also developed into cultural and intellectual centers, as trade brought in new ideas as well as merchandise. Universities offered courses of study based on classical models, and townspeople built churches and cathedrals as symbols of their Christian faith and their civic pride. New types of vernacular literature arose in which poems, songs, and stories were written down in local dialects.

In the fourteenth century a worsening climate brought poor harvests, which contributed to an international economic depression and fostered disease. The Black Death caused enormous population losses and social, psychological, and economic consequences. Additional difficulties included the Hundred Years’ War, a schism among rival popes that weakened the Western Christian Church, and peasant and worker frustrations that exploded into uprisings.