Ralph (Raoul) I de Tancarville (de Boscherville), Seigneur de Tancarville, Chamberlain to the Duke of Normandy - Family Tree of Raoul de Tancarville

http://fmg.ac/Projects/MedLands/NORMAN%20NOBILITY.htm#_Toc352825305

says
G. SEIGNEURS de TANCARVILLE


1. RAOUL [I] de Tancarville . The Chronique de Normandie, based on le Roman de Rou, names "le sire de Tancarville" among those who took part in the conquest of England in 1066[1761]. m AVICE, daughter of ---. Guillaume chamberlain confirmed the donation to the abbey of St Georges de Bocherville by Raoul, chief chamberlain of William I King of England, and his sons Raoul, Nigel and Guillaume, and their mother Avicia, with the consent of his sons Rabel and Robert and Lucy, recorded in a charter of Henry I King of England dated 1114[1762]. It is possible that she was the sister of Eudes Stigand, as shown by the charter of Henry I King of England, dated 1129, which confirmed an earlier donation to the abbey of Sainte-Barbe by "Odo Stigandus", at the request of "Guillelmi camerarii de Tancarvilla […nepos supradicti Odonis Stigandi] et Rabelli filii sui"[1763]. Raoul [I] & his wife had three children:
a) RAOUL de Tancarville . Guillaume chamberlain confirmed the donation to the abbey of St Georges de Bocherville by Raoul, chief chamberlain of William I King of England, and his sons Raoul, Nigel and Guillaume, and their mother Avicia, with the consent of his sons Rabel and Robert and Lucy, recorded in a charter of Henry I King of England dated 1114[1764].
b) NEEL de Tancarville . Guillaume chamberlain confirmed the donation to the abbey of St Georges de Bocherville by Raoul, chief chamberlain of William I King of England, and his sons Raoul, Nigel and Guillaume, and their mother Avicia, with the consent of his sons Rabel and Robert and Lucy, recorded in a charter of Henry I King of England dated 1114[1765].
c) GUILLAUME [I] de Tancarville (-1129). Guillaume chamberlain confirmed the donation to the abbey of St Georges de Bocherville by Raoul, chief chamberlain of William I King of England, and his sons Raoul, Nigel and Guillaume, and their mother Avicia, with the consent of his sons Rabel and Robert and Lucy, recorded in a charter of Henry I King of England dated 1114[1766]. "…Willo de Tancvilla…" subscribed the charter dated to [10 Apr/29 May] 1121 which records the arrangements for the marriage of "Miloni de Gloec" and "Sibilia filia Beorndi de Novo Mercato"[1767]. Henry I King of England confirmed an earlier donation to the abbey of Sainte-Barbe by "Odo Stigandus", at the request of "Guillelmi camerarii de Tancarvilla […nepos supradicti Odonis Stigandi] et Rabelli filii sui", by charter dated 1129[1768]. Henry II King of England confirmed the property of Savigny abbey, including the donation by "Guillelmi camerarii de Tancharvilla" of "landam de Tor", by charter dated to [1156/58][1769]. Henry II King of England confirmed the possessions of the priory of Sainte-Barbe-en-Auge, including donations by "Rabelli Camerarii…Willelmus camerarius pater eius…Willelmi Camerarii filii Rabelli", by charter dated to [1185/89][1770]. m MATHILDE d´Arques, daughter of GUILLAUME d´Arques & his wife Beatrix Malet. Guillaume de Jumièges records "Mathildis" as the daughter of “Willelmi de Archis”, adding that she married “Willelmus camerarius de Tancarvilla” by whom she had “filium Rabellum qui ei successit”[1771].

the three sons of Ralph
are Ralph, Nigel and William

Osbert is not listed here.