The Middle Ages (adjectival forms: medieval, mediaeval, and mediæval) is the period of European history encompassing the 5th to the 15th centuries, normally marked from the collapse of the Western Roman Empire (the end of Classical Antiquity) until the beginning of the Renaissance and the Age of Discovery, the periods which ushered in the Modern Era. The medieval period thus is the mid-time of the traditional division of Western history into Classical, Medieval, and Modern periods; moreover, the Middle Ages usually is divided into the Early Middle Ages, the High Middle Ages, and the Late Middle Ages.
In the Early Middle Ages, depopulation, deurbanization, and barbarian invasions, begun in Late Antiquity, continued apace. The barbarian invaders formed new kingdoms in the remains of the Western Roman Empire. In the 7th century North Africa and the Middle East, once part of the Eastern Roman Empire, became an Islamic Empire after conquest by Muhammad's successors. Although there were substantial changes in society and political structures, the break with Antiquity was not complete. The Eastern Roman Empire – or Byzantine Empire – survived and remained a major power. Additionally, most of the new kingdoms incorporated many of the extant Roman institutions, while monasteries were founded as Christianity expanded in western Europe. In the 7th and 8th centuries, the Franks, under the Carolingian dynasty, established an empire covering much of western Europe; the Carolingian Empire endured until the 9th century, when it succumbed to the pressures of invasion — the Vikings from the north; the Magyars from the east, and the Saracens from the south.
During the High Middle Ages, which began after AD 1000, the population of Europe increased greatly as technological and agricultural innovations allowed trade to flourish and crop yields to increase. Manorialism — the organization of peasants into villages that owed rent and labor services to the nobles; and feudalism — the political structure whereby knights and lower-status nobles owed military service to their overlords, in return for the right to rent from lands and manors - were two of the ways society was organized in the High Middle Ages. Kingdoms became more centralized after the breakup of the Carolingian Empire. The Crusades, first preached in 1095, were military attempts, by western European Christians, to regain control of the Middle Eastern Holy Land from the Muslims, and succeeded long enough to establish Christian states in the Near East. Intellectual life was marked by scholasticism and the founding of universities; and the building of Gothic cathedrals, which was one of the outstanding artistic achievements of the High Middle Ages.
The Late Middle Ages were marked by difficulties and calamities, such as famine, plague, and war, which much diminished the population of western Europe; in the four years from 1347 through 1350, the Black Death killed approximately a third of the European population. Controversy, heresy, and schism within the Church paralleled the warfare between states, the civil war, and peasant revolts occurring in the kingdoms. Cultural and technological developments transformed European society, concluding the Late Middle Age and beginning the Early Modern period.