During the War of the Spanish Succession, Felipe Mendoza, a Spanish soldier from Pensacola, was part of a Franco-Spanish expedition sent to investigate reports of English invaders at San Bernardo (Matagordo) Bay in Texas. After enduring a nightmare of privation and death, he appeared out of the wilderness alone at the Rio Grande post of San Juan Bautista. On orders of Francisco Martínez, commanding Santa María de Galve at Pensacola, Mendoza and two other Spanish soldiers had departed early in 1703 for Mobile to ask Jean-Baptiste de Bienville for a like number of French soldiers to join them. Told that the soldiers could not be spared from that post, they proceeded to Fort La Boulaye on the lower Mississippi. There three Frenchmen joined the expedition, but one of the Spaniards became ill and was left behind. After traveling thirty days upriver by pirogue, the three Frenchmen and two Spaniards journeyed west, then south over plains and through forests of pines and hardwood. After encountering a band of nomadic Indians (apparently Karankawan), Mendoza's Spanish companion was slain by the Frenchmen. Mendoza fled for his own safety, traveling west until he fell ill among an unknown tribe. At last, among the Coahuiltecan Payayas, between the Medina River and the Río Hondo, he encountered a Spanish-speaking native who directed him to San Juan Bautista. Sent thence to Mexico City, Mendoza deposed to Gregorio de Salinas Varona on October 24, 1703. Salinas found Mendoza to be familiar with the territory he himself had traversed with Alonso De León and Domingo Terán de los Ríos, and with the Texas coastal Indians. He concluded that Mendoza's tale was genuine. It appeared that Mendoza had proved the feasibility of overland travel from Santa María de Galve to San Juan Bautista. Salinas suggested that a force from Coahuila and Nuevo León, led by a more competent observer, be sent to reconnoiter San Bernardo Bay and examine Mendoza's route.
It was the French who heeded the message. A decade later, Louis Juchereau de St. Denis, who had chosen the French soldiers for the journey-and to whom they reported upon their return-made his storied trek across Texas to San Juan Bautista. As a result, Spanish officials realized that the time had come to occupy Texas permanently. A sequel to Mendoza's story is found in a statement sent by a French official at Mobile to a Spanish official at Veracruz in 1714. The Sieur de Montigny wished to hold the Spaniards accountable for salary, provisions, and equipment for the three French soldiers, whom he says were provided at Martínez's request-"one of whom was killed during the journey."