The paper makes a join between the lead burial plaque of William d’Aincourt at Lincoln cathedral, the clause concerning his parents’ gifts to St Mary’s abbey in York from the confirmation charters of the abbey, and two letters of Anselm to Gunnhild, daughter of King Harold. It argues that William d’Aincourt’s mother Matilda was most likely the daughter of Count Alan Rufus, since she alienates to St Mary’s York, Alan’s foundation, lands and tithes that belonged to him or his men in 1086. Matilda’s mother must have been Gunnhild, who was his only known ‘partner’—a relationship comprehensively misunderstood by Anselm and hence by R. W. Southern and half-a-dozen more recent writers. Count Alan’s ‘antecessor’ in his first English estates was Eddeua the fair, properly identified as King Harold’s wife Eadgifu Swanneshals, who was Gunnhild’s mother. Through Gunnhild Count Alan held her mother’s estates and in the next generation the d’Aincourt family claimed royal descent, but we find this sensational statement only in the obscurity of a burial plaque from a child’s grave.