The Swedish government has about a million (literally!) historical maps available online, unfortunately it seems the interface is only in Swedish…

https://historiskakartor.lantmateriet.se/

Here's an example, a regional map from 1654 including Gothenburg:

https://historiskakartor.lantmateriet.se/hk/viewer/internal/...

Also https://maps.nls.uk/ is a great place to explore old maps

No, I wasn't aware of that, thanks! I can really see how you can get hooked by something like this.

Superb website, very cool!