My child is quite into history and changing world boarders at the moment so I suggested we get some historial mapping data and make our own!
This article provided some ideas on where to look, so I thought I'd check out the first one listed that's found on the wayback machine. There appears to be a lot of caveats on the accuracy of these ones, but as a starter, it will do!
Used the steps I went through on Day Five and converted the shape files to geoJson then topoJson. The files weren't too big, so decided to skip simplifying them.
Used d3.geoEqualEarth() as the geo projection
Added labels. There is lots of overlap in Europe, so possibly next step,I'll work out a ounding box and create some maps that focus on their areas of interest.