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- Other publications have a range of incompatible ideas about his parentage.
- thePeerage, July 2010, citing only email correspondence, says "He was the son of Alan la Zouche and Constance of Brittany.1 He married Hawise Fergan." and shows an only child "Alan la Zouche b. 1157, d. 1190"
- Genealogics, July 2010, citing "~Histoire et Genealogie des maisons de Rohan, Chabot, de Rohan-Chabot , Martin, Georges , Reference: II 31" and "The Complete Peerage, 1936 , Doubleday, H.A. & Lord Howard de Walden , Reference: XII/2 930", calls him "Geoffroi Vicomte de Porhoët", and says his parents were "Eudon I, Vicomte de Porhoët et de Rennes" and "Anne de Leon", he married "Havoise" (who gave him two sons "Vicomte Eudon II de Porhoët, Duke of Bretagne 1148-1156" and "Alan Ceoche of La Coche, otherwise La Zouche"), and he died 1141/42.
More research is needed, probably starting with Medieval Lands: Brittany, which lists
- Children of CONAN de Bretagne (-17 Sep 1148) (oldest of the three children of Duke Alain IV & his second wife):
- "HOËL de Bretagne (-1156) ... (disinherited)"
- "BERTHE de Bretagne (-[1158/64]) ...
- "m firstly () ALAIN "le Noir" de Penthièvre, Lord of Richmond, son of ETIENNE de Bretagne Lord of Richmond & his wife Havise de Guingamp (before 1100-in Brittany 15 Sep 1146, bur Bégard).
- "m secondly (1148 or before) as his first wife, EUDES Vicomte de Porhoët, son of GEOFFROY Vicomte de Porhoët & his wife Hawise --- (-1170). He succeeded in 1148 as EUDES Duke of Brittany, by right of his wife. Deposed by his stepson in 1156..."
- "CONSTANCE de Bretagne (-1148). The primary source which confirms her parentage and marriage has not yet been identified. m as his first wife, GEOFFROY de Mayenne, son of JUHEL Sire de Mayenne & his wife Clémence de Ponthieu (-18 Feb or 25 Jul 1169)"
Second child of Duke Alain IV & his second wife was HAVISE de Bretagne, who "m (1110, divorced) BAUDOUIN de Flandre, son of ROBERT II Count of Flanders & his wife Clémence de Bourgogne [Comté] (1093-Boulers 17 Jun 1119, bur Saint Bertin). He succeeded his father in 1111 as BAUDOUIN VII Count of Flanders. "
Third was "GEOFFROY "le Roux" de Bretagne (-Jerusalem 1116)".
An illegitimate son of Duke Alain may be relevant to British genealogy: "BRIEN [FitzAlan] [FitzCount] ([1090/1100]-after [1141/42]). The primary source which confirms that he was the son of Alain IV Duke of Brittany has not yet been identified. According to the Complete Peerage, Brien FitzCount was the son of Alain "le Noir" de Penthièvre Lord of Richmond (who died in 1146) and his wife Berthe daughter of Conan III Duke of Brittany, but this is impossible from a chronological point of view. " So there. Was he Lord of Abergavenny? He gets 20-odd lines of discussion, which concludes that he probably had no heirs.