I am currently trying to learn more about local(Austrian) history, since my education was mostly focused on major events and the World Wars.
I live near the city of Wels, Upper Austria. Wels has a population of around 60k, but also the reputation of being the most boring, god-forsaken wasteland of a city which only exists to fill space on a map. But Wikipedia tells me that in its place used to be the city of Ovilava, home to 18000 people(at around 200CE). How big of a deal would a city this size have been for the Romans?
(As an aside, I would be interested in any further information about Ovilava, since I don't even know where to begin to look).
Hello there!
To answer your question directly, most Roman cities averaged in population between 5-15k permanent residents, not counting merchants and legionnaires that would also be in the area or passing through.
Ovilava with it's population of 18,000 would not only be a large city by standards of the day, but it was also a critical communications and transport hub for the Empire. First a colony of Rome itself, and then later a provincial capital of the province of Noricum, Ovilava with it's strategic crossroads and river crossing & access was the de facto center of the Danube front of the Empire.
An interesting comparison would be the city of St Louis during the American Western Expansion. So one could say that Ovilava was pretty important to the Empire during it's heyday!
Some follow up reading with academic sources can be found here:
http://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0006:entry=ovilava