Gabriel Moraga was a Spanish-California explorer and the first white man of record to visit this area. In April 1806, he discovered a river now known as the Tule, named it Rio de San Pedro, and followed its channel upstream possibly as far as River Island. Friar Pedro Munoz, Moraga's diarist, wrote that at the river mouth it was "without water due to its thickness of willow, cottonwoods, torote and ash trees, and also because of an abundance of sand," but that upstream there was enough good water and land to support a mission. Moraga also discovered an Indian rancheria "with 400 souls" in the area that now includes the Porterville Municipal Golf Course and Alta Vista. Known as Chokowesho and occupied by the Coyehete Tribe of Yokuts, this rancheria was in a way the forerunner of Porterville. Commanding a force of 25 men, Moraga had been sent into the San Joaquin Valley by California Governor Jose Joaquin Arrillaga to locate a possible site for a Spanish mission and to deal with neophytes who had run away from missions on the coast taking horses, cattle, and firearms. While exploring from the Calaveras River to the Kern River, Moraga crossed the Rio de San Pedro very close to this location.