Thorvald Asvaldsson was the father of the colonizer of Greenland, Erik the Red, and grandfather of Leif Ericson, who visited North America centuries before Christopher Columbus. Thorvald's father was Ásvald Ulfsson, whose father was Ulf Oxen-Thorisson, whose father was Oxen-Thorir, brother of Naddodd, discoverer of Iceland.