The
House of Percy (old French
Perci) were the most powerful noble family in northern England for much of the Middle Ages, having descended from
William de Percy (d.1096), a Norman who crossed over to England after
William the Conqueror in early December 1067, was created 1st
feudal baron of
Topcliffe in Yorkshire, and was rebuilding
York Castle in 1070. The name derives from the
manor of
Percy-en-Auge in Normandy, the home of the family at the time of the
Norman Conquest. Members have held the titles of
Earl of Northumberland or
Duke of Northumberland to this day, in addition to
Baron Percy and other titles. In common with their rivals, the
House of Neville, the Percy surname twice died out in the male line but was re-adopted by the husband of a Percy heiress and by their descendants. In the 12th century, the original Percy line was represented by Agnes de Percy, whose son by her husband
Joscelin of Louvain adopted the surname Percy. Again in the 18th century, the heiress
Elizabeth Seymour married
Sir Hugh Smithson, who adopted the surname Percy and was created Duke of Northumberland.