The Middle Ages began when Germanic tribes (peoples from northern Europe) invaded the western part of the Roman Empire. The tribes took over the land and formed many small kingdoms.
The invaders also eventually converted to Christianity, which had become the major religion of Rome. The church became the one thing that everyone had in common. The pope was the head of the Christian church. He and other church leaders became very powerful. Few people outside the church could read or write during the early Middle Ages. Religious communities called monasteries therefore were centers of learning.
The most successful king of this period was Charlemagne. He ruled the Franks in the region that is now France and Germany. The pope crowned Charlemagne emperor of the west in 800. However, his heirs were too weak to keep the empire—later called the Holy Roman Empire—in one piece.
From the 800s to the 1000s, Viking invaders attacked many parts of Europe. The Vikings came from what are now Denmark, Norway, and Sweden. They made trouble for many rulers.
During the 1000s, Europeans developed the feudal system to provide security. Landowners called lords built castles. They gave land to followers called knights. In return, the lords called on their knights to defend them in battle. People called serfs or peasants actually farmed the land. Serfs were not much better off than slaves.
