Seventh son of a seventh son, Sigurd's magical bloodline shouldn't have been a surprise, but no one had thought about it, really.
Sigurd is technically, maybe, nobility, but not important enough for anyone to track. Sigurd's grandfather is the baron of a minor holding - Sigurd's father is technically landed by virtue of his grandfather - but that makes Sigurd's claim so diluted he's barely above a bastard. By some interpretations of certain laws, he might rank below a bastard of a son with a higher claim!
So when Sigurd started accidentally turning house guests into newts when his magic began to manifest (they got better!), it seemed in everyone's best interest to have one less son under foot.
Now a few years removed, Sigurd can't accidentally turn anyone into newts anymore and has gotten a handle on his magic. But there is no love lost between him and his family, so he has gone off to the New World to seek a New Life where, just maybe, he'll be wanted.