It all began at the Canary Islands with the Guanches confronting the invaders and losing the control of the lands but not the identity of the invaders: the Godos (Goths)
Six hundred years later the islanders still refer to their fellow citizens in the rest of Spain as the "Godos", the Goths.
No better example can be used to explain the ephemeral qualities of national identities as opposed to the need to name our social groups, a constant in human categories. The invaders did not come as Spaniards as we understand the concept today but as "súbditos del Reino". It was the identity of the Reino what linked these groups at an earlier time and not the nation since it is not after the "reconquista" that such a concept came about.
As a teacher at CCNY I came across quite a few Latino and Latin American students (including a few professors also) who were not aware that their entrenched national identities were the product of recent historical events. When asked to explain when their identities were originally formed, under what political and historical conditions they were unable to do so. Some became quite defensive as if offended by such question.
And when told that as early as 200 hundred years ago many of them would have not being considered a citizen to vote (read Pico on the founding of Cayey, a mountain town in Puerto Rico to get an idea as to was considered a citizen during the Spanish colonial regime) and the reasons for such policy, they were on route to reshape histories.
With regards to criollos, when asked about this very Latin American identity, "nada de nada".