- Born on January 1, 1698 in Pontacq
Parents
- Jean François Antoine de Castelnau (c. 1645 - 1722), seigneur de La Loubère
- Jeanne de Cacaret (c. 1669 - 1700), dame de Liac
Family
- Married on February 7, 1724 in Nay, with Marie de Montesquiou (c. 1710 - ), issuing
