the monarchs were the ones who lost territory to the moors. yes, they were muslim/arab, but take a wild guess where most of their army came from... these people merged with the existing population, as was also the case in sicily.
so they were mixed race headed toward a new continent filled with exclusively non-whites. they merged with the people there, and i rest my case. i know they weren't technically half black, but they weren't purely caucasian either. lets not get caught up on semantics.