Dark Ages

The Dark Ages is a term popularly applied to the period of time following the collapse of the Roman Empire in Western Europe, a time that historians prefer to call the Early Middle Ages. The term has been used to describe the lack of education and economic collapse, which accompanied the political anarchy left in the wake of Rome's disappearance.
The Dark Ages was a period of population decline, and increased migration from "barbarian" tribes, such as the Goths, Vandals, and Huns from Eastern Europe and central Asia. Many of these tribes overran Roman provinces and established smaller kingdoms throughout Europe. This led to a general breakdown of trade and commerce, the decline of literacy and education, and the beginnings of feudal society.
Europe began to recover after about four centuries, marked by the development of manorial agriculture by AD 800 and the establishment of the Carolingian Empire of Charlemagne in central Europe. However, a new threat quickly put an end to the Carolingian Renaissance: the Vikings.
The Viking Age (793-1066) was marked by raids from Scandinavia, and the Vikings established political kingdoms and new trade networks throughout Britain, Ireland, Normandy, and southern Italy. It was in reaction to Viking incursion that many areas of Europe developed feudalism, one of the first structural advancements out of the Dark Ages.