Ancient royal lines often start with someone who is, as Neal Stephenson would put it, a stupendous badass. e.g. The current UK Royal Family have these chaps as

Ancient royal lines often start with someone who is, as Neal Stephenson would put it, a stupendous badass. e.g. The current UK Royal Family have these chaps as ancestors: https://en.wikipedia.org/wiki/Rollo https://en.wikipedia.org/wiki/Rollo https://en.wikipedia.org/wiki/Robert_the_Bruce https://en.wikipedia.org/wiki/Robert_the_Bruce