2021-10-15 20:16:51 UTC
"The place of my nativity is Killidy, in Ireland, in the county of Limerick, where I was born the 29th of September, 1678. My father was Peter de Lacy, son of John de Lacy, of the family of Balmgary [sic] Lacy in the said county of Limerick. My mother was Mary de Courtney, daughter of Thomas de Courtney, and of Catharine Nagle".
The 24 August 1740 Austrian confirmation of nobility for the field-marshal agrees that "[m]aternam vero Courteneorum stirpem inclytae nobilitatis fama in Anglia eminere" and the slightly later pedigree registered by his son gives his mother as “Maria de Courtenay aus Frankreich”. The implication, I assume, is that his maternal grandfather, Thomas Courtney or Courtenay, was a cadet member of the family of the Earls of Devon.
But how? The only man who seems to fit the bill in Ireland is Thomas Courtney of Castleblagh, co. Cork (plausibly proximate to Killeedy and Ballingary), who fl. 1675-1685  and the names of his descendants certainly echo those of the Devon family, but I can find nothing relative to his ancestry. I'd be grateful for any thoughts on this or, indeed, for any suggestions concerning the possible origin of his wife, Catherine Nagle.
All best wishes,