LA PEROUSE EXPEDITION 1785
By FB-AI Chat.-T.Chr.-Human Synthesis-30 October 2026
Jean-François de Galaup de La Pérouse (1741-1788), expedition chief and ship commander
La Pérouse Expedition
Jean-André Mongez
An exceptional collection of 12 previously unpublished autograph letters by the physicist Jean-André MONGEZ (Lyon, 1750 – Vanikoro, 1788). Seven of these letters were written during the expedition led by La Pérouse: two in Brest, aboard La Boussole, including one on the eve of departure on August 1, 1785; then one from Santa Catarina Bay in Brazil (November 13, 1785), one from Monterey, California (September 23, 1786), one from Macao (January 17, 1787), one from Kamchatka (September 21, 1787), and a final one from Botany Bay in Australia (February 5, 1788), the last port of call before the two ships were wrecked in mid-June 1788 on the Vanikoro reefs.
The other five letters were written between 1781 and 1784. All of this correspondence was addressed to the same recipient, Louise Victoire Le Cloustier (1750–1821), a resident of Rouen, daughter of a hydrographic engineer who was a member of the Académie de Marine and, from 1781 onward, wife of Jean Baptiste Du Hecquet, a cavalry captain. This private and intimate correspondence is not intended to recount in detail the vicissitudes of the journey, nor to report on scientific discoveries and observations. While there are numerous references to travel conditions and certain significant events, it is clear that Mongez is careful to spare his friend any worry about him.
The tone is often lighthearted, sometimes even humorous, which, under such conditions, speaks to a powerful strength of character! And the recurring theme is the young man’s return to his loved ones—the reunion.... One can imagine to what extent this thought—which seems almost obsessive to Mongez—enabled him to endure the worst travel conditions and keep his determination intact. Until this discovery, no firsthand source had allowed us to grasp what these letters of overwhelming intensity reveal: the most authentic, most touching portrait of one of La Pérouse’s companions, his deep feelings and emotions, from even before departure and throughout the expedition.
Another previously unknown detail, as curious as it is moving, is revealed by this correspondence. The letters written before departure shed light on the “true” reasons behind Jean-André Mongez’s decision to agree to take part in this perilous expedition. This question had remained unanswered until now, since, as a renowned physicist, a regular at Parisian salons, and a member of several academies, it seemed surprising that he would embark on such an uncertain adventure. Mongez addresses Louise Victoire as “my dear little sister (sic)” and refers to himself as her “dear little brother,” yet we have found no family connection between them. One letter reveals the immense grief that consumes him as Mademoiselle Le Cloustier’s wedding approaches; in another, he addresses the reproaches she has directed at him, to which he attempts to respond; he makes promises, he asks for forgiveness...
We are free to imagine that a relationship developed between this young woman and the brilliant canon of Sainte-Geneviève that may have gone beyond the bounds of mere friendship. He seems to eventually resign himself to it… but several passages suggest that while he is leaving “…partly out of a love of glory and a desire to acquire new knowledge…,” his primary aim is to achieve a form of redemption: “…I will be even more worthy of [your] friendship when I have improved myself….”
Jean-André Mongez’s autograph letters are extremely rare. We have identified no more than a dozen in France’s public collections, and they are exceedingly rare on the market. These were discovered in the archives of a French family. Finally, it is worth noting that Mongez mentions here on several occasions how fortunate he is to be in very good health. This would support the hypothesis that he is indeed the “Unknown Man of Vanikoro,” whose remains were discovered in 2003 during underwater archaeological expeditions conducted on the two shipwrecks...
The only available page of the original handwritten page in French
AI extraction/translation of the one original letter page -
The ten-month lease and in advance, under penalty of all dependencies, damages, and interest. And furthermore, to terminate the said lease to the good householder and father of a family and to reserve the fire. Agreed that in the event that Mr. Suberiaze the obituary of the said house should pass away and that the said leisure should be dispossessed of the said house, and to the tenant who would succeed the said Subariaze, this present police agreement shall be as if it had not occurred without, in the said event, the said Bernat being able to demand any damages on account of the non-execution of this present for the remaining delay.
AI extraction/translation of a second original letter page -
For The Astrolabe
Two rudder bars for the bot-
A peak for the stays
— three cramps for the hatch bars
— three padlocks for the same
Two dozen rings for the drailles
of the forces and veils of the country — [uncertain word]
What is mentioned above has not been
supplied with the rest of the filling.
On board on 10 June 1785
[Signature: The Redhead?] [Signature : De Mont?]
Frigate captain
[The Astrolabe
RARE LOVE LETTERS TO FRENCH ARISTOCRAT SHED LIGHT ON LOUIS XVI MARITIME MYSTERY.
