Leif and Ivar are both sons of Eric the Red, a Norse explorer who is credited with the first European settlement in Greenland. Leif, also known as Leif Erikson, was the first European to land in North America, while Ivar was a Viking chieftain who led a successful raid on England in 865. Both Leif and Ivar were important figures in Norse history and their father, Eric the Red, is remembered for his exploration and colonization of Greenland.