Primarily Eastern Europe but there is a lot of hidden history behind this one.
Fun Facts:
1. Tuscany conquered all of Naples by 1466, and has remained stable and relatively powerful ever since.
2. France owned all of Ireland and Scotland, up until the reformation hit and rebels swamped them
3. Novgorod practically tag-swapped into Finland. Nearly all their remaining provinces rebelled to Finland as Muscovy started to take them over.
4. Yes that's Montenegro.
5. Brandenburg has risen to 20+ provinces and collapsed back to 2 or 3 no less than 8 times.
6. Trier the OPM elector has an incredible desire for 42 of my provinces.
7. When Bulgaria revolted from the Ottomans, it took all of Moldavia's land with it at first, then Moldavia rebelled and formed the current borders.
8. The Teutonic Order once owned all of northern Poland and north-western Lithuania before collapsing to rebels
9. France has been in a war with Provence for over 45 years.
10. Rome is Protestant