San Bernardinos east of Cajon Pass and permitted trade between people of the Inland Empire basin and the Mojave Desert. San Gorgonio Pass, which forms the largest natural break in the Transverse Ranges, also allowed interaction between coastal and desert tribes. River canyons, especially those of the Mojave and Santa Ana, provided the major means of entry to the mountains. Many archaeological sites have been discovered along Deep Creek, a tributary of the Mojave River, in particular. Explorers and early settlers During the 17th and 18th centuries, various Spanish explorers passed through coastal Southern California and claimed the area for Spain. In 1769, the Spanish government began an effort to bring what they called Alta California under their control and introduce Christianity to native peoples through the construction of missions. It was not until 1772 when the military governor of Alta California, Pedro Fages, became the first European known to reach the San Bernardino Mountains. Although the original purpose of his expedition was to pursue deserters from the Spanish army, he ended up venturing into not just the San Bernardinos but also the San Jacinto Mountains, the Mojave Desert, and eventually north into the Central Valley. The San Bernardinos and their surrounds were sporadically explored throughout the next 50 years or so - first by Francisco Garcés, the first known European to use the Mojave Road, in 1776, followed by José Maria de Zalvidea, who surveyed the Mojave River area in 1806. In 1810, Francisco Dumetz led a small company to build a temporary chapel near what is now Redlands. On May 20, the Feast Day of Bernardino of Siena, Dumetz named the San Bernardino Valley. This name was applied to San Bernardino Peak by 1835, and was in wide use for the entire range by 1849. In 1819, San Bernardino de Sena Estancia was created near present-day San Bernardino as an outpost of nearby Mission San Gabriel Arcángel. Although sometimes referred to as an asistencia, or "a mission on a small scale with all the requisites for a mission, and with Divine Service held regularly on days of obligation, except that it lacked a resident priest", San Bernardino was really just an estancia, or cattle ranch. In 1820, a -long irrigation ditch or "zanja" was dug using Native American labor to furnish water from Mill Creek, a major stream flowing out of the San Bernardinos, to the estancia and