Early Middle Ages partially coincident with Late Antiquity
The Early Middle Ages (or early medieval period), sometimes controversially referred to as the Dark Ages, is typically regarded by historians as lasting from the late 5th or early 6th century through the 10th century. They marked the start of the Middle Ages of European history, following the decline of the Western Roman Empire, and preceding the High Middle Ages (c. 11th to 14th centuries). The alternative term late antiquity, for the early part of the period, emphasizes elements of continuity with the Roman Empire, while Early Middle Ages is used to emphasize developments characteristic of the earlier medieval period. 
The period saw a continuation of trends evident since late classical antiquity, including population decline, especially in urban centres, a decline of trade, a small rise in average temperatures in the North Atlantic region and increased migration. In the 19th century the Early Middle Ages were often labelled the Dark Ages, a characterization based on the relative scarcity of literary and cultural output from this time, although the term is scarcely used by academics today.  However, the Eastern Roman Empire, or Byzantine Empire, continued to survive, though in the 7th century the Rashidun Caliphate and the Umayyad Caliphate conquered swathes of formerly Roman territory.
Many of the listed trends reversed later in the period. In 800, the title of Emperor was revived in Western Europe with Charlemagne, whose Carolingian Empire greatly affected later European social structure and history. Europe experienced a return to systematic agriculture in the form of the feudal system, which adopted such innovations as three-field planting and the heavy plough. The migration of various tribes stabilized in much of Europe, although the Viking expansion greatly affected Northern Europe.
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