Population size and growth rates in Western Europe 0-1998
Plague of Justinian, which the source claims to have killed around one third of the continent's population (although recent studies dispute this). Similarly, the population fell by almost 17 million throughout the 14th century, due to the Black Death.
Improvements in agriculture and infrastructure then saw population growth increase once more from the 15th century onwards, before the onset of the demographic transition saw a population boom throughout the 19th and 20th centuries.
Throughout the Common Era, Western Europe's population development fluctuated greatly. The population was very similar at the beginning and end of the first millennium, at around 25 million people. The largest decline in this period occurred in the sixth century, due to the Improvements in agriculture and infrastructure then saw population growth increase once more from the 15th century onwards, before the onset of the demographic transition saw a population boom throughout the 19th and 20th centuries.