Firmin René Desloge
Firmin René Desloge (17 February 1803, Nantes, France – 20 July 1856, Potosi, Missouri) was a U.S. businessman who founded lead mines and other mercantile businesses. He was the progenitor of the Desloge Family in America, whose Missouri business interests included fur trading, hardware, clothing, lead smelting and ore trading, and distilling.
Desloge’s great-grandfathers included Jean Mosneron, a nobleman of Bretignolles, Luzon, who lived in Nantes; nobleman Gildas Alexiz Pitault; Francois Rozier, a lawyer in the Parliament of Paris, Bailiff of the Forte’, Sancerre, Ingra and other jurisdictions of the Bailiwick of Orleans; and Michel Rozier, an officer of the Mint and Marshall of the Minters of the Orléans Mint. His grandfathers included Francois Claude Rozier, Mayor of Kernegan from August 1789 and Judge of the Tribunal of Commerce from Jan. 23, 1793. Desloge's father, Joseph Giles Desloge, was appointed Mayor of Morlaix by the French First Empire. His uncle (by marriage to his father’s sister Marie-Marguerite) was Jean-Baptiste Sollier de la Quillerie, a member of the French king’s gendarme.
In 1806, Firmin's uncle Jean Ferdinand Rozier immigrated to the Louisiana Purchase territory of Missouri. He was accompanied by and in business partnership with John James Audubon, on a journey funded by Desloge's grandfather, Claude Rozier.
Firmin followed in 1823, and was introduced by his uncle and Audubon to the businesses of fur trading and mercantile interests along the Ohio and Mississippi rivers and "nearly" All His Descendants and lead smelting and mining in Potosi, Missouri. St. Genevieve, on the Mississippi River and of strong French descendency, was a hub for trading with Indians and new white arrivals to the frontier.
Desloge began to focus on lead mining. He had a nose for lead veins and geology, and began with open-ground diggings, some left open by Indians and frustrated miners. He built a smelting furnace around 1824 as an extension of his Potosi mercantile business.
Desloge became a naturalized citizen of Missouri in 1828.
His son, Firmin Vincent Desloge expanded the family mining and mercantile operations, becoming one of the richest men in the world at his death in 1929. Around 1932, Desloge's estate was valued more than $52 million 
- Douglass, Robert Sidney (1912). History of Southeast Missouri: A Narrative Account of Its Historical Progress, Its People and Its Principal Interests, Volume 1. Chicago and New York: Lewis Publishing Company. p. 557. Note: the cited paragraph is primarily about Firmin V. Desloge, but contains a relevant sentence about his father, Firmin Rene.
- “Descendance de Joseph-Gilles Desloge.” 2 pp. typewritten, n.d. Translated by Rosemary T. Power. Missouri Historical Society Archives, Joseph Desloge Collection
- Huger, Lucie Furstenberg. The Desloge Family in America. St. Louis: Nordman Printing Co., 1959
- The Rozier Collection at Missouri Historical Society, St. Louis, MO
- Arthur, Stanley Clisy. Audubon: An Intimate Life of the American Woodsman, 1937
- Between the Gabouri: A History of Ferdinand Rozier [detail with Firmin Rene Desloge], by Mary Rozier Sharp, Louis James Sharp, Histoire de Rozier,1981, pages xxi through 46
- State Historical Society of Missouri, Rozier Store Records R132, http://shs.umsystem.edu/rolla/manuscripts/r0132.pdf
- Rozier's History of the Early Settlement of the Mississippi Valley, Firmin A. Rozier, G.A. Pierrot & Sons, 1890, pages 286, 288, St. Louis County Library Closed Stacks
- Early Lead Mining on the Upper Mississippi. Reuben Gold Thwaites In R.G. Thwaites, George Rogers Clark and Other Essays in Western History. Freeport, N.Y., Book for Libraries Press. 1903
- Potosi (Missouri) Historical Society
- Joseph Desloge Collection, 1812-1963: Description, Missouri History Museum.
- Probated will of Lydia Desloge, source Farmington (Missouri) Press, December 1932