de Lacy (Laci, Lacie, Lascy, Lacey, Lassey) is the surname of an old Norman family which originated from Lassy, Calvados. The family took part in the Norman Conquest of England and the later Norman invasion of Ireland. The name is first recorded for Hugh de Lacy (1020–1085). His sons, Walter and Ilbert, left Normandy and travelled to England with William the Conqueror.[1][better source needed] The awards of land by the Conqueror to the de Lacy sons led to two distinct branches of the family: the northern branch, centred on Blackburnshire and west Yorkshire was held by Ilbert's descendants; the southern branch of Marcher Lords, centred on Herefordshire and Shropshire, was held by Walter's descendants.
Until 1361, the northern branch of the family held the great Lordship of Bowland before it passed through marriage to the Duchy of Lancaster. They were also Barons of Pontefract and later (via two female lines) Earls of Lincoln.
The southern branch of the family became substantial landholders in the Lordship of Ireland and was linked to the Scottish royal family; Elizabeth de Burgh, great-granddaughter of Walter de Lacy, married Robert the Bruce, King of Scotland.