(Spinoff off this thread)
The project I’m working on right now is a dungeonpunk fantasy novel set in a country that looks a lot like medieval Iceland and Norway and has a plot involving a young cutpurse who’s fostered by a dwarven fence. The narrator’s name is Bjarki Thórinsson. The patronymic is his foster father’s name given to him when he was adopted. He was born in a hospital (in the medieval sense) sent to a nurse and given a first name.
That leads to the question. What patronymic would Bjarki have been given before he was taken into the hospital? Is/was there a generic Icelandic patronymic for a child whose parents are unknown? The fact that he doesn’t have any known relatives is an important plot point.