The period that followed the fall of the Western Roman Empire is often referred to as the Middle Ages, specifically the Early Middle Ages, which some historians term the Dark Ages. This era, lasting from around the 5th to the 10th century, was characterized by a decline in cultural and economic activity in Western Europe. During this time, much knowledge from the classical period was lost, cities became less populated, and centralized government disappeared in many areas. The term "Dark Ages" is somewhat controversial, as it can undervalue the complexities and developments that occurred, including the rise of Christianity and the consolidation of kingdoms.