 He appears to have been the son or grandson of Lambert, a nobleman of the Maasgau, the area where he later founded the Abbey of Thorn, and to have been related to various important contemporaries including the royal family.The principal source of information regarding Ansfried is the "De diversitatem temporum" by the Benedictine Albert of Metz, written around 1022.Ansfried had the same name as a paternal uncle ("patruus"), Ansfried the elder, a count who supposedly held 15 counties.