Born 24 February 1367 and baptised 25 February 1367 at Church of St Margaret, Lincoln Cathedral. Alison Weir discusses the claimed birth dates for Thomas in Katherine Swynford pp. 79-81.
↑ Weir, Alison. Katherine Swynford : The Story of John of Gaunt and His Scandalous Duchess. London: Vintage Books, 2008, pp. 79-81.
Alison Weir, Britain's Royal Families: The Complete Genealogy (London, U.K.: The Bodley Head, 1999), p. 102.
G.E. Cokayne; with Vicary Gibbs, H.A. Doubleday, Geoffrey H. White, Duncan Warrand and Lord Howard de Walden, editors, The Complete Peerage of England, Scotland, Ireland, Great Britain and the United Kingdom, Extant, Extinct or Dormant, new ed., 13 volumes in 14 (1910-1959; reprint in 6 volumes, Gloucester, U.K.: Alan Sutton Publishing, 2000), volume IV, page 64.
Royal Ancestry by Douglas Richardson Vol. V pp. 373, 390
It may be possible to confirm family relationships with Thomas by comparing test results with other carriers of his Y-chromosome or his mother's mitochondrial DNA.
However, there are no known yDNA test-takers in his direct paternal line.
Mitochondrial DNA test-takers in the direct maternal line: