Hi Joe,
It's a bit more more complicated than that. It's taken me a long time to work out the genealogy of this family. Henry son of Conan of Manfield, Kelfield, Liverton, etc. married Juliana, by whom he had at least three children, Conan, Margery and Elizabeth. Henry died before August 1285 (CFR, i, 219). Conan son of Henry married Pernel de Burton, daughter of Roger de Burton and Joan de Meinill and widow of Humphrey son of Geoffrey de Conyers of Sockburn. She was the mother of John de Conyers (c. 1272- c.1303). Their son and heir Henry son of Conan was born at Sockburn on 21 September 1277 (CIPM, iii, 498, No. 623), when his father was only about 15 years old. Conan son of Henry died in the lifetime of his father before 1285, probably about 1282.
John de Conyers, son of Humphrey de Conyers and Pernel de Burton married Elizabeth, daughter of Henry son of Conan and sister of Conan son of Henry, Pernel's second husband (I told you it was complicated). This John de Conyers also had a bigamous marriage to a lady called Margaret from Northamtonshire, as shown in the following case from the Common Pleas:-
14 October 1304, York, Quindene of Michaelmas, 32 Edward I, Margaret who was the wife of John de Coigners by her attorney claimed against Elizabeth the daughter of Henry Conan, a third part of a third part of a messuage, 20 tofts, 30 carucates and 50 bovates of land, a windmill and a watermill in Rounton [Rungeton], Girsby [Griseby] and Dinsdale [Dytenes Hale], and against Anthony, bishop of Durham, custodian of the lands and heir of John son of Humphrey de Coigne[rs], a third part of the other two parts of the same lands in the same vills. Elizabeth and the bishop appeared by their attornies and denied that Margaret was entitled to dower in the lands because John had espoused (disponsavit) Elizabeth when aged 7 years, and she had remained his wife throughout his life and at the time of his death was seised as his lawful wife, and that Margaret was ever joined to John in lawful matrimony (umquam … legitimo matrimonio copulata). Margaret replied that she was espoused (disponsata fuit) at Maidwell [Maydewelle] in Northamtonshire in the diocese of Lincoln and was joined to John in lawful matrimony (eidem Johanni legitimo matrimonio copulata). The bishop of Lincoln was ordered to inquire into the truth of the matter and report to the court at Westminster in the quindene of Hilary [27 Jan 1305]. He didn’t, and the order was repeated thrice, with successive new deadlines of 3 weeks after Easter, the quindene of St John the Baptist and the quindene of St Martin [13 Oct 1305]
Court of Common Pleas: CP 40/149 m. 98.
http://aalt.law.uh.edu/E1/CP40no149/aCP40no149fronts/IMG_0207.htm
Regards,
John