Juan José Flores the younger was born in Saltillo in 1743, the son of Juan José Flores de Abrego y Valdés and Nicolasa de Ávila. After the death of his wife the elder Flores moved to San Antonio de Béxar. On February 3, 1750, he married Leonor Delgado, the widow of Bernardo Leal. Around 1756 they started a ranch near San Bartolo on the lower Cibolo Creek, one of the earliest in the vicinity. Flores the younger, his three brothers, and his sister eventually left Saltillo and joined their father in Texas. In 1777 Flores, his wife, and two children were residents of Presidio del Río Grande, the old San Juan Bautista. The family kept close ties with their native city, however. When the elder Flores died in 1779, all the children but one were mentioned in his will, along with his three children by Leonor Delgado. Flores soon petitioned the estate for 900 pesos owed to Francisco de Yermo, an administrator of tithes in northern Coahuila. This sum was apparently owed in connection with the annual tithe that the elder Flores had collected in Texas. Flores began driving herds of livestock, branded and unbranded, to the Rio Grande to fulfill his father's obligation to Yermo.
In so doing he soon ran afoul of Governor Domingo Cabello y Robles, who had the thankless job of taxing unbranded livestock-decreed the property of the king-taken from the province. By mid-1784 Flores had fled Texas, carrying petitions against the cattle tax directly to the commandant general. He remained in Chihuahua during Cabello's term of office, little more than a fugitive from justice, and continued working for the stockmen's interests. Because of these labors the ranchers were granted additional time to gather and brand their "stray" stock, thereby avoiding the tax.
After Rafael Martínez Pacheco replaced Cabello as governor, Flores returned to Texas and acted as the private raisers' agent in negotiating a roundup agreement with the missions of San Antonio de Béxar and La Bahía in 1787. He probably authored the "San Fernando Memorial," one of the most comprehensive stock-raising documents of eighteenth-century Texas. In the early years of Martínez Pacheco's administration several cattle drives were made to Coahuila by the citizens of Bexar in order to pay Flores for his defense of their rights.
Unfortunately, the cattlemen's attorney did not live to see his protests bear fruit. He was killed at his ranch by Apaches in March 1790, leaving a widow, Manuela de Aguilar, their three children, and a large debt owed to San José y San Miguel de Aguayo Mission. Flores's legal efforts were not entirely in vain, however. Five years after his death the viceroy and a council of the Royal Treasury canceled all debts owed the king's Mustang Fund; nevertheless, they ordered the old detested fees on wild livestock to be collected after a final roundup extension of one year. See also RANCHING IN SPANISH TEXAS.