Manuela Sánchez Navarro y Gomes Mascorro, the daughter of Diego Sánchez Navarro y Camacho and Mariana Gomes Mascorro y Garza, was baptized in Monclova, Coahuila, Mexico, in 1697. Despite never having lived in Texas, she figures as prominently as any other woman in the early history of the region. Her paternal grandmother, Feliciana Camacho y Botello, was married first to Diego Sánchez and afterward to Commandant Diego Ramón. When Louis Juchereau de St. Denis arrived on July 19, 1714, at San Juan Bautista Presidio (at the site of present-day Guerrero, Coahuila), Ramón placed him under house arrest in compliance with a 1713 viceregal order prohibiting entry of foreign traders or their merchandise into Spanish territory. Word of the Frenchman's presence was forwarded to the viceroy, who did not respond until the following March. During the intervening months of St. Denis's detention he became engaged to Manuela. News of the impending union reached the viceroy in Mexico City before St. Denis arrived there to face charges and defend himself. He no doubt knew his engagement to Manuela would enhance the chances for his successful outcome in Mexico, since the viceroy knew that Manuela was directly descended from several of the military, political, and financial elite of New Spain. After St. Denis's exoneration, on August 22, 1715, the general junta appointed him conductor of supplies for the planned Ramón expedition to Texas. Under the command of Domingo Ramón, the commandant's son, the 1716 expedition was instructed to reestablish Spanish missions in East Texas. This expedition was the first step in permanent Spanish occupation of lands northeast of the Rio Grande.
The year of Manuela's departure from New Spain to join her husband is uncertain. Whether she joined him first in Mobile, Alabama, or Natchitoches, Louisiana, also is a unknown. Earliest census records for Poste St. Jean Baptiste des Natchitoches, where St. Denis assumed command in 1721, indicate that the first two of the couple's children were born in New Spain. Manuela could have joined St. Denis in the French colony as early as 1719 but no later than 1721. They eventually had two sons and five daughters, including Marie Petronille Feliciane, who married Athanase de Mézières on April 18, 1746. Whatever problems existed to keep St. Denis out of New Spain, they were resolved by 1743. In January of that year he wrote the French crown requesting permission to resign his command at Natchitoches, retire from the crown's service and, with his wife and minor children, move to New Spain. Months later his request to retire was granted, but his request to move to New Spain was denied. To compensate him for the rebuff, the French crown assured St. Denis that his children would be placed as advantageously as possible in the royal service. St. Denis died in Natchitoches on June 11, 1744. Manuela, a widow at age forty-seven with three or four minor children, remained in Natchitoches. She continued to live in the house St. Denis built for her on property now occupied by the campus of Northwestern State University of Louisiana. She died in Natchitoches on April 16, 1758. The St. Denis children and their families played significant roles in the continuing development of Texas, Louisiana, and New Spain.