Secondat, Jean-Baptiste de

François Cadilhon

1Born on 10 February 1716 at Martillac, Montesquieu’s only son, the eldest of his three children, was sent very early to study in Paris at the Collège Louis-le-Grand under the direction of Father Castel. The philosopher wanted him to be able to take up the ancestral office of président à mortier at the Bordeaux parlement, and prepared him carefully for a definite social life in Bordeaux. On 2 November 1736, Montesquieu offered him a charge as counselor and subsequently negotiated his marriage in 1740 with Marie Catherine de Mons, daughter of François Antoine Joseph de Mons, baron of Soussans and Bessan, heir of an old Bordeaux family of which he was jurat (a municipal title). Jean-Baptiste de Secondat had no desire to carry out what his father had been unable to pursue and almost never took his seat in the city parlement. At the death of Albessard, from whom the office was leased, Montesquieu finally had to sell his office on 4 August 1748 and Jean-Baptiste abandoned his on 10 June 1748 to devote himself to his personal research.

2Elected to the Bordeaux Academy on 4 November 1734 at his father’s request, he became fully involved in it. Often director, vice director or perpetual secretary, in alternation with François de Lamontaigne, he defended a social opening-up of the institution, until then largely reserved to the parlementary elites, and proposed the creation of contests and prizes much less theoretical than the first ones, this time on rural economy or social problems. On his own, avoiding Bordeaux societal evenings, he multiplies at home experiments on electricity, demographic evolution, mineral waters. During regular trips to the Pyrenees, he scaled the Pic du Midi to study the map of the skies or to compare the works of Fahrenheit and Réaumur. He thus created by correspondence a solid European scientific reputation. In 1755, after a notice granted to his father, he was entitled to an article in La France littéraire for his Observations de physique et d’histoire naturelle.

3Jean-Baptiste de Secondat had to negotiate for several years over his father’s legacy and come to an agreement with his sister Denise, to whom he finally abandoned Montesquieu properties in Agen. While complaining often of his financial situation to his friend the marquise de La Ferté-Imbault, daughter of Mme Geoffrin, he was all the same one of the largest landholders in the Bordelais, in Graves, l’Entre-deux-Mers and Médoc. According to the tax registers of 1776, there were fourteen nobles in the Bordelais who had to pay more than 200 livres, and the baron de La Brède was one of them. Enthused by the agronomical vogue of the 18th century, he studied all the new theories and supported the creation of an agricultural society in Guyenne, encouraged by the royal government but blocked by the parlement. Jean-Baptiste de Secondat hoped for the political and economic changes proposed by Turgot, but finally blocked by the resolute hostility of the members of parlement. The baron, made uneasy by the intellectual and political tensions, took care to control carefully and limit the publications of his father’s works, going so far in 1783 as to transform the end of Arsace et Isménie so as to avoid scandalizing anyone by the (unacceptable) suicide of the hero (see OC, t. IX, 2006, p. 305-368). The weight of the memory of his too-illustrious father accentuated his solitary and misanthropic character. At the Bordeaux Academy, while the new laureates generally ended their reception speeches with an homage to the author of L’Esprit des lois, he often responded with reflections on Montaigne.

4In 1787, he suggested a series of reforms at the meeting of the Assemblée des notables in an anonymous memoir, Amateur de la vérité (Pensées d’un amateur de la vérité sur les affaires présentes, to be found in the Bordeaux city library under the call number D60323; see also MS 2695/3); though the memoire is anonynomous, citizen Secondat was to present himself as its author when interrogated during the Revolution (AD Gironde 14 L 34, Cadilhon, p. 222). But being too old, he took no part in the political movements and the French Revolution. In January 1794, he was nevertheless arrested by the Bordeaux Jacobins because his only son Charles Louis had emigrated to serve in the royal armies of the princes. His property was placed under seal and after being finally freed, he struggled to obtain restitution until his death on 17 June 1795.


Jules Delpit, Le Fils de Montesquieu, Bordeaux: P. Cholet, 1888.

Michel Figeac, Destins de la noblesse bordelaise, 1770-1830, Bordeaux: Fédération historique du Sud-Ouest, 1996.

Carole Rathier, “Les réseaux des Lumières à Bordeaux, étude de correspondances, 1768-1788”, doctoral thesis, Université de Bordeaux 3, 2007.

François Cadilhon, Jean-Baptiste de Secondat de Montesquieu: au nom du père, Pessac: Presses universitaires de Bordeaux, 2008.

Julien Vasquez, Nicolas Dupré de Saint-Maur: le dernier grand intendant de Guyenne, Bordeaux: Fédération historique du Sud-Ouest, 2008.