CastaƱo de Sosa…Basque?

Baltazar CastaƱo de Sosa is my direct 11th great grandfather. In other words, from father to son, my paternal lineage. Although I descend from him in other lineages within my family history, I find this ancestor of mine quite unique. While investigating my ancestry, I took two DNA test, one from 23andme, and the second…