By "pure" I mean that the Royal Family is fully (or almost fully) from that country.
It's no secret that there's a lot of German blood in the British Royal Family or that the Swedish monarchy comes directly from a (French I guess) Napleon marshall.
Are there any Royal Family without that much blood from foreign monarchies? I guess, though, that in the end at some point in the family tree they always end up and have ended up marrying with foreign princes and princesses