Groa is often mentioned as a concubine. At this time, a concubine was a wife of lesser importance, often the daughter of a slave or servant. In the Orkneyinga Saga Ragnvald is quoted as telling his son, Einar, "Considering the kind of mother you have, slave born on each side of her family, you're not likely to make much of a ruler. But I agree, the sooner you leave and the later you return, the happier I'll be.""