When discussing the languages of the Christian Kingdoms of the Iberian Peninsula during the High Middle Ages, there is usually a very neat delineation, corresponding to the political entities of the time: Galician-Portuguese, Astur-Leonese, Castilian, Basque, Navarro-Aragonese and Catalan. This seems suspicious, to me. One hypothesis to explain this one-to-one correspondence is that the political entities formed emanated from a coherent and well-defined demos in each case, each having its own dialect/language. The convoluted and haphazard way in which these political entities came about makes me dislike this hypothesis. The other hypothesis is that these are just labels applied to a cluster of dialects spoken in each realm, being that one could have more or less labels, depending on how many political entities had been formed. So, my question is, given how similar the languages in question are, excluding Basque and Catalan, is it likely there would have been a dialectal continuum between them? Or is considering the existence of four distinct and separate languages/dialects a better way to frame the issue?

Thanks.