Call her Matilda.
Your grandmother & Matilda's grandparent = 1st cousins
Your parent & Matilda's parent = 2nd cousins
You & Matilda = 3rd cousins

She will probably meet that special someone and have children before you do. But, 5 - 15 years from now you will too, probably. Those children will be 4th cousins to each other.

It depends on who is asking.

If it's a passport control officer, you're an American.

If it is a friend who came to dinner and wonders how your mom learned to cook so well, you're half Polish and half Italian.

If it's a girl your age with sparkling brown eyes and a dimple (assuming you are a straight male), it's complicated, and you'd be glad to explain it over a cup of coffee, and have her tell you about hers.

Never heard of the last name until now but here is some info about the name.

(Russian) , Polish, and Czech: from the Late Latin personal name Romanus, originally an ethnic name meaning 'Roman' (a derivative of Roma; compare Romolo). This name was borne by a large number of early saints, and in the 10th century was given as a baptismal name to Boris, son of Vladimir, the ruler who Christianized Kievan Russia. Boris and his brother Gleb were murdered by their brother Svyatopolk and canonized as martyrs. Use of the name in the English-speaking world is recent, influenced perhaps by the film director Roman Polanski (b. 1933 as Raimund Liebling).

1. There is no "blackfoot tribe". There are 5 tribes that speak the blackfoot language. 4 of them are in Alberta, Canada. The BlackFEET tribe in northern Montana is very small, just a few thousand families, so if she's enrolled there, it will be easy to locate her records. Where was she born?

2. There are northern and southern Cheyenne. (in Montana and Oklahoma) Which one is he? And if he qualified for citizenship, he would have been enrolled (not "registered") at birth. And the BIA would have issued him a CDIB . So there would be ample records of him as a tribal citizen, whether he "embraced" being so or not.

Part of your problem is you are looking for proof of your family stories, instead of just following the history and seeing where it goes.

What is your grandfather's name and where was he born, and when?
What is your grandmother's name and where was she born, and when?

Post that info, and we can check the tribal census records for you, or tell you where to look. Have you checked and found them listed on the US census records?

How can I find out who my grandfather was?

My dad's dad is someone we never talk about, my dad's mum married a few times and I saw my dad's birth certificate in a drawer and his birth surname was different, meaning that my grandfather isn't who I grew up thinking he was. I've checked ancestry.org and findmypast, no luck, how can I find out who my grandfather was?

If you wish to spend money on entertainment, which is only what this advert is, then that is up to you, it will tell you nothing, but it will make the company money and it might entertain you and if you don't like the results you can always entertain yourself again and have another one and they will send you different results, in fact they will send different results each time you pay for it............. as ancestry doesn't change clearly it is junk......... as for ethnicity you already know exactly what ethnicity you are , as ethnicity means YOUR customs, cultures, affiliations and associations in the home and in the country YOU were born/live in so the food YOU eat the language YOU speak........ it is NIL to do with your genealogy......if you wish to know where your ancestors came from then the ONLY way to find that out is to research this helps you do that it is 100% free and is nowhere on line but you will find the records in your own home http://familytimeline.webs.com/recordsin...