Biggest Cities of Europe in 500 AD with a Map

Please note that this is in the middle of the Dark Ages, and that it's pretty much the most difficult medieval period to get population estimates for, as most of my data starts around 700 AD.

Most of Europe at this time was devastated and depopulated due the barbarian invasions, which made it very difficult to collect data for the region. Events that caused other major demographic changes, like the Plague of Justinian (the death toll of which is still unclear), the Gothic War of 535-554 that depopulated the Italian peninsula and the Avar–Byzantine wars of the late 6th century/early 7th century in the Balkans that caused much destruction and leveled many urban centres were also yet to occur.

This means that information here might indeed be subject to error, but there's unfortunately not much I can do about that.