Spanish naming customs, a little confused (search, Mexican, typical, last name)

[Count David]

So ancestry.com just "leaf"'d something regarding one of my paternal great-grandfathers. Basically, the guy who gave me my last name. We'll call him Steve.

I know nothing about him, however, my brother appears to have been named after him. My grandfather (whom I did know when I was young, we'll call him Sam) was brought to the U.S. by Steve from Mexico at the age of 6. Where in Mexico.......beats me (?). Nobody was even sure of the exact year my grandfather Sam was born (it was 1911 or 1912, nobody was ever sure). No Mexican record of Sam, other than U.S. records saying he was born in Mexico as well.

Anyhow, the Ancestry leaf found a Mexican baptism record of a guy (Steve) that could be my great-grandfather, only his birthdate that my tree had for him was exactly a year off, but the same date, Dec 26.

Steve was born very deep into Mexico, quite close to Guatemala actually. Steve had only my last name listed in the record (twice, for some reason), his father (we'll call him Chris) had my last name as well, but it was listed second.

Here's where I'm confused and/or interested. Chris's first name and first last name are stereotypically Portuguese, but his second last name was my last name, which came from his mother's dad (per Chris's baptism record). Chris's father and grandfather's first/last names are also stereotypically Portuguese (both same last name as Chris's first last name).

So I'm wondering, did somebody make a mistake in naming somewhere? It appears Steve took Chris's mother's last name upon entering the U.S. (or at birth), or somebody screwed up, and I and my descendants should actually in theory have this Portuguese last name instead.

Anybody ever see anything like this before? Upon further research, it appears that my last name is quite popular in the part of Mexico in question, if that at all matters. The Portuguese name not as much, but it is present.

[AntonioR]

Plenty of Portuguese migrated to all parts of the Spanish Empire as Spanish subjects (basically ethnic Portuguese with Spanish nationality.)

Mexico has a tradition that people can choose which last name they put first and which second, if I'm not mistaken.

Double last names (one last name that appears as the first and second last name) is usually an indication that the person is the son/daughter of two closely related cousins that married each other.

It may also be indicative, and bases on the details you gave I think this is more likely in your case, of a sort of feud or estrangement between the offspring and one of his parents, albeit the usual practice is to adopt both maternal (or paternal if the issue is with the mother) last names and not using the same last name twice unless the paternal or maternal last names in use also repeat themselves.

Furthurmore repeating last names may mean that two untrelated persons (as far as they know) with the same last name married.

Lastly, all sorts of tricks and falsifications are done when people migrate from one place to another, especially if the migration has an air of illegality.