Brittany

The northwestern corner of France is a region called Breton, or Brittany, and they speak a non-Romance language, it is Celtic.

How often have they rebelled? How often have they acted differently than the main body of French people in terms of alliances or acquiescence to decisions of government?

One rather famous person, William the Conquerer, ruled Brittany and England. Of course, that rather confuses the issue, since the Norman conquerers were speaking French and/or a Viking language, and not Celtic. Brittany was ruled regularly from England between 0 and 1000 CE.

Even though the Carolingian Empire controlled most of France, Germany, Italy and the Low Countries , they created a special military administrative division, the March of Brittany, to deal with the Bretons. They only created on other march, for the Normans.

And certainly for hundreds of years the region, Domnania and Cornwall were part of a political unit that ignored the geographic proximity of the far larger Neustria or Aquitaine and were linked across the channel.

During much of the 100 years war, Brittany was in English hands. It certainly was close, but so was the area around Amiens, while all of Guyenne was much farther than Amiens.

The social distance between the language communities meant that Brittany was the poorest and most backward area of France before World War I (Peasants Into Frenchmen)