In the 1770s and 1780s, Muñoz worked in several "posts" in the Rio Grande region, "negotiated" with one of the Apache tribes (particularly with the Mescaleros) and carried out several military campaigns against the Native Americans of the frontier who resigned the Christian religion.
[5] However, in 1796, Muñoz fell ill and asked King Philip IV for permission to resign as governor.
In January 1797, Muñoz received news that the governor of Coahuila, (modern Mexico), Manuel Antonio Cordero y Bustamante, had been chosen by the king to replace him.
However, at that moment, Bustamante was commanding a war against the Apaches and he could not attend to his duties as governor, so Munoz continued governing Texas "until further notice".
[2][4] In March of that year, Cordero sent him a letter saying that he had been appointed lieutenant governor of Nuevo Santander, and that therefore he could not govern Texas.
[2] Finally, a year and a half later, in June 1798 José Irigoyen got the position of interim governor, but he couldn't serve either.