[dsantiago]

Jose Ortega y Gasset was a relative of mine, and I asked this as a kid. What I was told (by my grandmother, his niece) is that it is sometimes done when there's a weirdness in the combination of the two last names that would make it ambiguous, such as someone who has a compound first name like Jose-Maria that makes it harder to tell where a first name/last name breaks, or in this case, where it results in a repeated sound (ga-ga) that feels weird to say. But I have not found any corroboration of this online.

[unclebucknasty]

It has now been officially documented online by your grandmother via you. I'd take her word for it!

[phreeza]

I used to live on the street in Madrid named after your great-great uncle, and I always wondered why he was named like that. The explanation make sense!

[axtscz]

Thanks for answering. As a Spanish speaker this makes sense. My dad is from Mexico and no one in my entire family has this so maybe it's limited more to Spain?

[faragon]

It was until the 19th century, when it was somewhat normalized (census, etc.). Since the 20th century naming in Spain is pretty the same as Mexico and other Spanish speaking countries. All my known relatives names/surnames are without "y".

[dsantiago]

Yep, we are talking about someone who was born in the 1880s. Though as a counterexample in the modern age, there is a well-known Spanish economist at Columbia named Xavier Sala i Martin.