Galicia and when Spanish separated from Portuguese.

I have wondered at the "end of the line" origins of m Family surname, (ORNELAS) and am now down to about 5 serious contenders, all in the Galician region (Northern Spain/Portugal), and talking to several people who are absolutely certain that THEIR research and findings are accurate. We have Fornelas,(spain) Hornelas, Ornelas, and a few others with common phonetics from the region.

Realizing, that for a lot of us, some of our surnames come from a mother culture that is Galician, and regional, rather than strictly nationally Spanish or Portuguese, I began to wonder when the two languages formally separated, and found this interesting article.
https://www.quora.com/At-what-point-did-Portuguese-and-Spanish-become-distinctly-separate-languages

I am interested in what some of the older and more experience researchers here think, and looking to learn more.

Thanks.
Piero