|SOME NOTES ON MEDIEVAL ENGLISH GENEALOGY|
Volume 11, page 609, note n:
Cal. Inq. p.m., vol. ix, no. 598. John de Segrave of Folkestone was the son of his [John, Lord Segrave's (d. 1353)] father's yr. br., who m. Juliane, da. of John de Sandwico, and d. June 1343, leaving the above-named John, who d. July 1349, having had by his wife Blanche a da. Mary aged 15 at his death. She d. 1 Sep. 1349 (Idem, no. 295; Idem, vol. viii, no. 463). See also Cal. Fine Rolls, 1347-56, p. 329.
(Lord Segrave's "father's younger brother", the father of John de Segrave of Folkestone, was also named John.)
In the inquisitions taken after the death of John de Segrave of Folkestone, his daughter Mary is said to be 15 days old, not 15 years. The inquisitions giving her age are those for Kent (taken 22 August 1349) and Essex (taken 22 October). The dates given for John's death are 8 July and 23 September, and those for Mary's are 25 August and 1 September. But these seem to be contradicted by the dates of the earliest writs issued after their deaths - 18 May for John and 24 August for Mary.
No information is given about the wife of John de Segrave of Folkestone in the sources cited. It seems possible that the name Blanche has arisen out of confusion between this John and another John, the son of John, Lord Segrave (d. 1353), who had in 1349 a papal dispensation to marry Blanche, the daughter of John, Lord Mowbray (see Complete Peerage, vol. 9, p. 384, note e).