The Spanish state is an entity that was formed after hundreds of years as the result of the amalgamation and union of various kingdoms and territories. Eventually, the Castilian identity and language grew to be the dominant one among the Spanish regions and it's what most of us associate with being the "default" Spanish culture. What's weird is that historically, Castile itself used to be just a small county among the others such as Leon, Navarre, Aragon, etc.
My question is that, given the Iberian peninsula's history of diverse kingdoms and identities, how and why did the Castilian identity become the dominant one? And even more specifically, why are only Catalonia and the Basque Country (perhaps we can also include Galicia) the regions which insist on being different than the "default" Spanish culture? Why did the Leonese, Aragonese and Cantabrians more or less "accept" being Spanish and now speak Castilian instead of their own regional languages?
Thanks in advance.
Follow-up question: When the "Spanish" crown expelled the Muslims, Jews etc was there any effort to "Castilian-ize" the remaining population, specially in southern Spain/Andalusia? If yes, did that have any impact in further solidifying the Castilian culture as the dominant one?
Without getting into the present day, both the Leonese and the Cantabrians have had since the return of the Spanish Republic in the 1970s (or not long afterwards) had regional parliaments which have a certain amount of local autonomy, and there are still a certain number of people who do speak
Franco himself was not a big fan of the local provinces having power- he rolled back what decentralization had occurred during the Second Spanish Republic in the 1930s. National government policy strongly focused on a centralized Spanish nationalism, with the usual cherry-picking off certain events and activities to create a national mythos. Even local 'rights' which dated from medieval times were abolished in many if not all regions, particularly, if not always, in places that had been Loyalist strongholds during the Spanish Civil War.
Catalonia and the Basque Country were among the strongest loyalist areas during the Civil war, though I don't know if their feelings of nationalism dovetailed with support of the Republic or not.
Dictator Francisco Franco, despite being from Galicia himself, did include trying suppress Galician as a language and culture during his time in office. Once he was 'still dead' those efforts ramped down. As I understand it (and it has been a long time since I read the book(s) where I learned this) there is considerable debate over whether or not Galician is a Portuguese dialect or not- and where one comes down on THAT has a lot to to with how (and what sort) of nationalist one might become.