Mary Belasyse was the daughter of Thomas Belasyse, 1st Viscount Fauconberg of Henknowle and Barbara Cholmeley. She married John Darcy, 4th Lord Darcy, son of Michael Darcy and Margaret Wentworth, on 7 November 1624. She died on 14 September 1625.
Cokayne, George Edward, The Complete Peerage of England, Scotland, Ireland, Great Britain and the United Kingdom, Extant, Extinct, or Dormant (London: St. Catherine Press, 1910.), 4:77
Burke, Sir John Bernard, A Genealogical History of the Dormant, Abeyant, Forfeited, and Extinct Peerages of the British Empire (London: Pall Mall, 1883.), p. 40,
It may be possible to confirm family relationships with Mary by comparing test results with other carriers of her ancestors' mitochondrial DNA.
Mitochondrial DNA test-takers in the direct maternal line: