There are many different versions regarding who his parents were. Many web-based genealogies claim him to have been a son of Saint-Sauveur, while others position him in the le Goz family. Based upon a number of factors, the latter is more likely.

In "Les Barons du Cotentin", local Cotentin (Normandie) historian Alan Davies lists four sons as the children of Turtain Gotz (Thurstan le Goz) and Judith de Monterolier:

• Renouf (mort avant 1090)
• Turstin (Turtain) Haldup, ancestre des barons de La Haye-du-Puits
• Gislebert d'Avranches
• Richard Gotz, dit RIchard d'Avranches (1024-1082), vicomte de lieu en 1050, epousa Emma de Comteville demi-soeur du duc Guillaume

Davies says that Thurstan Haldup was Baron of La Haye-du-Puits et du Plessis; possessed numerous domaines in the Cotentin and Calvados and was the founder of the Abbaye of Lessay in 1056, with the accord of the bishop of Coutances (Geoffroy de Montbray). He died before 1080. From his marriage with Emma/Anne of Normandie, daughter of Richard II, he had notably two sons:

• Raoul, senechal for Count Robert de Mortain, died on crusade. Father of Robert, who became seigneur de La Haye following the death of his uncle Eudes.
• Eudes-au-Capel, baron of La Haye, senechal of Normandy.

Eudes appeared in many charters around 1080, and undertook to resolve the disputes of his office. Benefactor of the Abbey of Lessay, Eudes was buried there 3 Feb 1098, leaving the barony without posterity (no offspring).

His successor was his nephew, Robert de la Haye (Senior), son of Raoul, who inherited the seigneurie and died before 1154. From his marriage with Muriel de Colswein de Lincoln was born

• Richard, baron de La Haye, and
• Raoul, seigneur de Montchaton (on the Seine River, next to the chateau de Regneville), who had many offspring.

The brothers were at the defense of Cherbourg against Geoffroy Plantagenet. Richard, constable of Normandy, baron de la Haye, died in 1169. In 1154 he founded the Abbey of Blanchelande. From his marriage in 1140 with Mathilde de Vernon dame de Varenguebec, were born three daughters, of whom Gillette, who married Richard II du Hommet. Thus the barony of La Haye-du-Puits entered into the Hommet family.

Please note that Davies' account contrasts with that of Cawley in that Davies names Raoul (Ranulf) as the son of Thurstan while Cawley posits that it was in fact Thurstan's daughter who was married to Raoul/Ranulf.

From Charles Cawley's Medieval Lands database: http://fmg.ac/Projects/MedLands/NORMAN%20NOBILITY.htm

FAMILY of THURSTAN HALDUP

1. THURSTAN [Richard] Haldup (-after 1079). "Ricardus qui vocatur Turstinus Haldup cum Anna uxore sua, Eudoque filius eorum" founded the abbey of Essay by undated charter, dated to [1079/87][63]. Henry I King of England confirmed the possessions of Holy Trinity, Lessay, including the donations by "Ricardus qui vocatus est Turstinus Haldup et Eudo filius eius", by charter dated 1126[64]. Henry II King of England confirmed the possessions of the abbey of Lessai, including donations by "Turstini Haldup et Eudonis filii eius" confirmed by "Roberti de Haia et Murielis uxoris sue et Richardi et Radulfi filiorum eorum", by charter dated [1185/Jan 1188][65].

m ANNE, daughter of --- (-after 1079). "Ricardus qui vocatur Turstinus Haldup cum Anna uxore sua, Eudoque filius eorum" founded the abbey of Essay by undated charter, dated to [1079/87][66].

Thurstan & his wife had four children:

a) EUDES (-after [1081]). "Ricardus qui vocatur Turstinus Haldup cum Anna uxore sua, Eudoque filius eorum" founded the abbey of Essay by undated charter, dated to [1079/87][67]. Henry I King of England confirmed the possessions of Holy Trinity, Lessay, including the donations by "Ricardus qui vocatus est Turstinus Haldup et Eudo filius eius", by charter dated 1126[68]. Henry II King of England confirmed the possessions of the abbey of Lessai, including donations by "Turstini Haldup et Eudonis filii eius" confirmed by "Roberti de Haia et Murielis uxoris sue et Richardi et Radulfi filiorum eorum", by charter dated [1185/Jan 1188][69]. [Vicomte de Contentin. "…Eudo vicecomes Constantini…" witnessed the charter dated to [1060] under which Guillaume II Duke of Normandy granted "Brenerias" to the abbey of Bayeux[70]. Delisle suggests that Eudes was the son of Thurstan Haldup. However, it appears more likely that he was the younger brother of Vicomte Néel [II].] "Eudo filius Turstini" donated his part of "villa…Helville" to the abbey of Marmoutier by charter dated to [1081][71].

b) EMMA (-[1090/95]). She is named by Orderic Vitalis, who also names her father, and as children of her marriage, Guillaume, Reginald, Petronilla, Geva and "several other sons and daughters"[72]. Orderic Vitalis records that, after the murder of her husband, she took refuge with her brother Eudo "steward of the Duke of Normandy" (with which title he must be distinguished from Eudes de Rie, son of Hubert de Rie, see UNTITLED ENGLISH NOBILITY), and passed "almost 30 years of honourable widowhood there"[73]. m ARNAUD d'Echaffour, son of GUILLAUME & his first wife Hiltrude --- (-I Jan [1065]).

c) daughter . Her parentage and marriage are confirmed by the foundation charter of the priory in which her son Robert de La Haye names himself "son of Ranulf the seneschal of Robert de Mortain" and "nephew of Eudo dapifer" [son of Thurstan Haldup][74]. m RANULF, son of ---. Seneschal of Robert de Mortain.

d) ADELAIDE . Henry II King of England confirmed the possessions of the abbey of la Trinité de Caen, including the donation by "Adelaidis filie Tustini Haldup" of "alteram medietatem ville de Carpiquet", by charter dated to [1180/82][75].

Vital Statistics Thurstan (known also as Richard) Haldup. Died after 1079. Married Emma of unknown parents. Early Norman lord who founded the abbey of Essay with his son Eude and daughter Emma. Four children:

1. Eudes, died after 1081.
2. Emma, died between 1090 and 1095. Confirmed children: Guillaume, Reginald, Petronilla, Geva, and several other sons and daughters. Widowed when her husband was murdered and took refuge with her brother, Eude, steward of the Duke of Normandy.
3. unnamed daughter, who married Randulf, son of ___, Seneschal of Robert de Mortain. Her son was Robert de La Haye.
4. Adelaide.

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in Notes and Queries: A Medium of Intercommunication for Literary Men, General Readers, Etc. Ninth Series, Volume VIII, July-December 1901 [online on Googlebooks]

WILLIAM THE CONQUEROR’S HALF BROTHERS AND SISTERS. (9".1 S. viii. 199, p. 293.)

Orderic Vital (bk. vii. chap. xvi.) calls Harlowen de Burgo Herluin de Conteville. This place is Conteville-sur-Mer, near the mouth of the Risle. He states that he married Harleve, and had two sons. Mr. Cobbe gives him two sons, Odo and Robert, and a daughter named Adelaide, who married Eudes de Champagne for her first husband. and secondly Lambert Count of Lens. Her daughter Judith married Waltheof, Earl of Northumbria. Planché says there were two daughters—Emma, who became wife to Richard, Viscount of the Avranchin, whose son was the Earl of Chester; and Muriel, who married Eudo do Capello or al Chapel; but he states in vol. i. (‘Conqueror and his Companions ’) that there was also a sister of Muriel who became the wife of the lord of Ferté Macé, who was called
nephew of Odo in a charter. But he says (vol ii p. 286) that a sire de Ferté Macé, either Mathias or William, married a sister of Odo, and William, his son, was Odo's nephew. He does not know which sister of Odo, or by which father, or whether a child of Herleve and Herluin.Here lies a doubt which I have been seeking to solve, but at the present I am totally in the dark.

WHB Chesterton, Cambs.

Reply by Frances Selena Vade-Walpole, Stagsbury, Banstead, pp. 525-526

THE ‘Dictionnaire de la Noblesse ’ of 1774, by M. De la Chenaye-Dubois, says, under ‘La Haye du Puis,’ that early in the eleventh century it was in the possession of Richard Turstin called Bardouf, who founded in 1056, with his sister Anne and his son Yvon Capel, the Abbey of Lessay two leagues south of the Haye du Puis. Under ‘De la Haye,’ another family, it gives references to La Roque’s ‘Histoire de Harcourt,’ tome ii. p. 1101, c. This ancient noblesse descends from Renaud I, Sovereign Count of Burgundy, and Alix, daughter of Richard II, Duke of Normandy and Judith of Brittany, and is a branch of the Counts of Vernon.

Robert de la Haye, third son of Guy of Burgundy, Count of Vernon and Brione, accompanied William the Conqueror at the battle of Hastings, and confirmed the foundation of the Abbey of Lessay by the advice and with the consent of his wife Muriel and his two sons. He married Muriel daughter and heiress of Eudes au Capel, Grand Maitre d’Hotel to the Duke of Normandy, son of Richard Turstin “dit" Bardouf, or Haldup, and Emma, daughter of one of the Dukes of Normandy. According to the charters and La Roque. tome ii. p. 267. Henry I recommended the Abbey of St. Evroult to the Bishop of Lisieux, the Count of Mortain, and Robert de la Haye.

Count Robert of Mortain founded St. Evroult in 1082 with Matilda de Montgoméri, his first wife. Eudo de Capel’s estates went to his grandson, according to the French ‘Noblesse,’ for his daughter and heiress Muriel de la Haye du Puis married Robert de la Haye, of another family, and had Richard and Raoul.

Richard had only three daughters: he married a cousin, Matilda de Vernon heiress of Varanguebec. The eldest daughter had for her share the barony of La Haye du Puis, also Varanguebec from her mother. She married Richard, Baron du Hommet.

Odo Bishop of Bayeux, had a son John, who had for his preceptor Roger (see Sauvage, ‘ Recherches sur l’arrondissement de Mortain’).

Robert, Earl of Mortain and Cornwall, married first Matilda de Montgoméri daughter of Roger de Montgoméri, Earl of Shrewsbury, by whom he had William and four daughters. He married second Almodis, and had a son Robert.

William, second Earl of Mortain and Cornwall, married Adelidis, called “de Ou ” in a charter (‘ Calendar of Documents preserved in France,’ by J. H. Round, Charter No. 1209, date 1100-6). He became a monk at Bermondsey in 1140. Taken prisoner at Tinchebray and blinded.

Emma married William, Earl of Toulouse, and was great - grandmother to Eleanor, heiress of Aquitaine, who married first Louis, King of France, then Henry II, King of England.

Agnes married Andre de Vitre; her daughter Hawisa married Robert de Ferrers, first Earl of Derby.

Denise, so called by La Roque and Moreli, or Agatha by Anselm, married Guy, Sieur de Laval.

Barbe married Baudouin du Bose, fourth son of Antoine de Cluny; she had four sons, and died 1127. (French ‘Noblesse’ under ‘ Radeport,’ vol. xi. p. 662.)

Maude, Matilda, or Adelais.—Anselm says Eudes de Champagne, son of Henry, called Stephen, Count of Troyes and Meaux, second son of Eudes II, called Champénois, Count of Blois, Troyes, and Meaux, and of his wife Ermengarde of Auvergne, married Adelais de Mortaing, widow of a Norman seigneur, daughter of Helvin, Seigneur de Conteville and Herleve. Adelais founded the priory of St. Martin d’Aumale.

Brooke calls her Matild, half-sister by the mother to the Conqueror, and Vincent does not correct him. ‘L’Art de Verifier les Dates’ calls her “ soeur utérine." Maseres, ‘ Selects. Monumenta,’ in pedigrees, p. 389, calls her “soror uterina Gulielmi I ” TIn notes, p.316, she is called half-sister to the king, by Harleva or Arlotta and Herluin, “probus miles.” Also p. 250 says the same: p. 254 (in Latin), Orderic Vital says, “Odoni vero Campaniensi nepoti Theobaldi Comitis, qui sororem habebat ejusdem Regis (filiam scilicet Rodberti Ducis) dedit idem Comitatum Hildernessae.” She married first Enguerraud or Ingleram, Sire d’Aumale, killed 1053, leaving one daughter, Adelaide, supposed d. s.p.; married second, before a year of widowhood, Lambert, Count of Lens, brother to Eustace II, Count of Boulogne, who was killed next year, leaving one daughter, the “wicked” Judith, married to Waltheof ; her third husband was Odo of Champagne, by whom she had one son, Stephen, who became Count of Aumale.

Harlowen de Conteville married first Frédégonde, and had by her Raoul de Conteville, who came to England and had posterity (see House of Ivry).

Secondly he married Arlotta, or Herleva, and had by her Robert, Earl of Mortain; Odo, Bishop of Bayeux; Maud, or Adelais (perhaps), Countess of Albemarle.

Emma married Richard Goz, Earl of Avranches ; she was mother to Hugh Lupus, Earl of Chester. Brooke calls her Margaret. Vincent does not correct him.

Isabel married Guilbert, son of the Earl of Corbeil.

Muriel married Eudes al Chapel.

The ancestry of Harlowen is so far unknown. There is no trace of a John, Earl of Comyn, and the descent through Godfrey de Bouillon, who lived a century after, is of course absurd. The mistake has arisen most likely from Baldwin IL, King of Jerusalem, being called “Du Bourg ” (see ‘Art de Verifier les Dates’). He was father of Millicent, Queen of Jerusalem, whose jewelled prayer book is in the British Museum. Baldwin II was a “parent" (may mean nephew or cousin) to the brothers Godfrey and Baldwin I; he was son of the Count de Rethel, in Champagne.

Pére Anselm, vol. ii. p. 470. says Harlouin de Conteville is by some called Gilbert de Crépon.