Louis Juchereau de St. Denis
He was born at Beauport, New France, the eleventh of the twelve children of Nicolas Juchereau (1627-1692), Seigneur du Chesnay and Saint-Roch-des-Aulnaies; member of the Sovereign Council of New France. His paternal grandfather was the elder brother of Noël Juchereau des Chatelets. His mother, Marie Thérèse Giffard de Beauport, was the daughter of Robert Giffard de Moncel, Sieur de Moncel à Autheuil, and the 1st Seigneur of Beauport, Quebec. His brother was the grandfather of Louis Barbe Juchereau de Saint-Denys (1740-1833), 1st Marquis de Saint-Denys, ancestor of Marie-Jean-Léon, Marquis d'Hervey de Saint Denys
His parents apparently were able to send St. Denis to France to further his education. In late 1699, St. Denis sailed from La Rochelle with the second expedition of Pierre Le Moyne, Sieur d'Iberville (a relative by marriage), arriving in Louisiana. St. Denis commanded a fort on the Mississippi River and another at Biloxi Bay. He also explored to the west of the bay and upstream, where he journeyed to the lower Red River. These expeditions brought St. Denis into contact with the Karankawa and Caddo tribes and taught him invaluable wilderness skills specific to the area.
Antoine Laumet de La Mothe, Sieur de Cadillac, sent St. Denis and a company of men from Mobile in September 1713 to travel up the Red River and establish a French outpost. St. Denis arrived in Natchitoches later that year and built a fort. He traded with the Indians and freely sold them guns. The French learned many hunting and trapping skills from the Indians.
Soon after founding Natchitoches, St. Denis traveled to the lands of the Hasinai Confederacy and from there to Spanish outposts on the Rio Grande. At San Juan Bautista, Coahuila, Commander Diego Ramón placed St. Denis under house arrest and confiscated his goods while awaiting instructions from Mexico City on what to do with the foreigner charged with violating Spanish trade restrictions. In the meantime, St. Denis courted and won the promise of marriage from Ramón's beautiful step-granddaughter, Manuela Sanchez. St. Denis was ordered to Mexico City and defended himself well enough to be appointed the commissary officer of the Ramón expedition charged with founding Spanish missions in East Texas.
St. Denis returned to San Juan Bautista and married Manuela in early 1716. In the years 1716-1717 he traveled to East Texas to participate in the founding of six missions and a presidio. He returned to San Juan Bautista in April 1717, but with the death of Louis XIV and the conclusion of the War of Spanish Succession, French-Spanish cooperation had ended. St. Denis was then sent to Mexico City for a second time but escaped before being hauled to Spain as a prisoner. St. Denis made his way to Natchitoches by February 1719. Spanish officials permitted Manuela to join him in 1721 and the couple spent their remaining years there at the French outpost, Le Poste des Cadodaquious, on the Red River.
Later life 
From his command at Natchitoches St. Denis was a troublesome thorn in the side of Spanish Texas. Controversy surrounds his motives to this day. St. Denis insisted that he desired to become a Spanish citizen, and his Spanish wife was proof. Suspicious Spaniards saw him as a covert agent of France. St. Denis contributed greatly to the geographical knowledge of both France and Spain as well as bringing Spanish and French settlements into closer proximity and contact. His contraband trade became a way of life on the frontier and borders of Spanish Texas and French Louisiana.
On 10 January 1743, he wrote to Jean-Frédéric Phélypeaux, comte de Maurepas, at Versailles indicating that he could no longer perform his duties as commandant of Natchitoches. He also asked permission to retire to New Spain with his wife and children, but he was forbidden to do so. St. Denis died at Natchitoches on 11 June 1744. He was survived by his wife and five children, one of whom was married briefly to Athanase de Mézières.
As his two sons did not bear any children of their own, his daughters carried his posterity. His descendants, among others, include: Jefferson J. DeBlanc and Alcibiades DeBlanc, who founded the Knights of the White Camellia.
- Famille de Juchereau de Saint-Denys, Juchereau du Chesnay/Duchesnay
- Fehrenbach, T.R. Lone Star A History of Texas and the Texans. Collier Books: New York, 1980. pp 41-43.
- Chipman, Donald E. Spanish Texas 1519-1821. University of Texas Press: Austin, 1997. p 105