So? The question was "Where you get that he was Croatian in the first place?" and the answer is that he was born in what is now Croatia. I'm sure that, if you took a survey, plenty of people would say the Dalai Lama is Chinese.
About a billion people agree with you, and a billion people don't.
The other several billion do not give a shit, even under the most promising of conditions, because they have real, actual, human problems in their modest, meager, live-a-day lives.
Are you fucking stupid, sir? Or are you simply ignorant? Do you not understand this is the very meta-issue that finds itself under debate? Are you incapable of abstract thought?
People often confuse ethnicity and nationality - you need to be more concrete with your example.
Two Caucasians (ethnicity) who are US citizens living in China gives birth to a baby in China, then the baby would be Caucasian (ethnicity), and American (nationality, by US law), but probably also Chinese (nationality, by Chinese law[1]).
Maybe that example is not so great because the baby would have dual-citizenship, so consider a different example:
3rd generation Chinese immigrants in the US who are born in America, never left the US to visit China (same as their parents), it is their grand parents who migrated from China. These 3rd generation immigrations are Chinese (ethnicity) and US citizens (nationality), also called Chinese-Americans (format: [ethnicity]-[nationality])[2]. These Chinese-Americans are not citizens of China, but they are ethnic Chinese.
Hope that clears up that one small point.
[1] Most countries have a 'if you're born here, you get our citizenship automatically' (I'm not sure about China specifically, just using it as an example).
[2] easy to mix up and confuse, but order matters here
> Most countries have a 'if you're born here, you get our citizenship automatically' (I'm not sure about China specifically, just using it as an example).
That principle is called 'jus soli'[1], and is far from universal. Only ~15% of all nations confer it. A few more grant it under restricted conditions. China is emphatically _not_ one of those countries.
Did you mean the Caucasian ethnic groups -- i.e., Chechens, Ingush, Ossetian, et al, or the "Caucasian race" (which is itself a misnomer) -- whites. These are completely separate things.
The term Caucasian is highly confusing as it's a racist term invented by the same German who came up with Negroid and Mongloid, and is - as far as I know - only used in the United States. In fact, the Supreme Court in United States v. Bhagat Singh Thind (1923) decided that Indians were "Caucasian", but were not white.
Also, China is a bad example, as Chinese is not an ethnicity, it's a nationality as China is a multi-ethnic nation. The ethnicities being Han (what most people consider to be "ethnic Chinese", Hui, et al.
Huh? The answer is actually no. Not just for the legal (and or trivial) reasons that he wouldn't have neither the ethnicity not the nationality, but he also wouldn't share the chinese culture.
What kind of Americans? Say they are a Sioux-Polish American from Chicago and an Irish-Mexican-Mongolian American from Houston, then yeah, why not call the kid Chinese. My mate was born on holiday in Australia and only lived there for a week, yet had to go through naturalisation over 20 years later to become the same nationality as his parents, as they had forgot to fill out the forms at the time.
So presumably Tesla was a Croatian-Serb, or possibly a Serb-Croatian, and whether or not those two groups get along doesn't really affect that definition. I mean, I fully understand that it is a touchy subject, but I don't really think that it affects long dead physicists very much.
>What kind of Americans? Say they are a Sioux-Polish American from Chicago and an Irish-Mexican-Mongolian American from Houston, then yeah, why not call the kid Chinese.
It's still American.
(At least to us Europeans) what matters is the culture of the parents/kid, not the nationality or the ethnicity itself.
A 3rd generation Irish-American is an American, not an Irish, and a 3rd generation Chinese-American is by all means an American too.