From Pacy-sur-Eure, arrondissement of Evreux. Pacy, which anciently belonged to the Frank kings and the Carlovingians, came into the possession of duke Rollo, who annexed it to the ducal domain. Richard I, duke of Normandy, granted it to Herfast, the brother of his wife, who was the father of Osberne de Crepon, and grandfather of William Fitz Osberne. A strong castle existed there from a very early date, which as time wore on came into increasing prominence, and as late as 1222 king Philippe Auguste of France sojourned there. William Crispin I was the possessor of a large amount of property in Pacy which is made evident by his many donations to the abbey of Bec before 1070. [ William Crispin I gave to the abbey of Bec before 1070 one-sixth of the mills at Pacy, one half of the forest there belonging to it, and l00 solidi of the customs of that citadel. ] When he was appointed hereditary viscount of the Norman Vexin by duke William, about 1045, the castle of Pacy came under his command, it being one of the border fortresses in this district. The seigniory of Pacy was in possession of William Fitz Osberne at the time of the conquest, consequently there could not have been another sire de Pacy then, as affirmed by Wace (l. 13655), unless he meant to chronicle William de Breteuil, eldest son of William Fitz Osborne, who succeeded to this seigniory at the death of his father in 1074. If this assumption is incorrect, then he referred to someone who held under Fitz Osberne, though probably not entitled to be designated "sire de Pacy." There was at that time a William de Pacy (Willelmus de Paceio) apparently of considerable importance, who with his mother Hadwis gave lands to the abbey of Bec c. 1070. He would appear to be the same William de Pacy, possibly castellan of Pacy, who was among the witnesses of a charter in favour of St-Evroult, by Raoul de Toeni II, between 1087 and 1099. Ranulf Flambord, bishop of Durham, deprived of that see by king Henry I, acquired the bishopric of Lisieux for his son Thomas, a mere child. He governed it himself, not as a bishop, but as a prevost, and was compelled to relinquish it after three years. The bishopric of Lisieux was then purchased by his clerk, William de Pacy, for a large sum of money paid to duke Robert Courteheuse, "but being condemned for his simony, first at Rouen and afterwards at Rome, he paid dearly for his presumption." (Orderic)

Another William de Pacy c. 1135, son of Matilda, made a donation to the abbey of St-Taurin, with the consent of his suzerain, William de Breteuil. [ If Le Prevost was correct in placing this charter in 1135, then this William de Breteuil was the son of Eustache de Breteuil, known as William de Pacy, seieneur de Pacy and de Breteuil, who died in 1152.]

--(This name appears on the Falaise Roll)