In 1772, Anza proposed an expedition to Alta California to the Viceroy of New Spain. This was approved by the King of Spain and on January 8, 1774, with 3 padres, 20 soldiers, 11 servants, 35 mules, 65 cattle, and 140 horses, Anza set forth from Tubac Presidio, south of present-day Tucson, Arizona. Anza heard of a California Native American called Sebastian Tarabal who had fled from Mission San Gabriel to Sonora, and took him as guide. The expedition took a southern route along the Rio Altar (Sonora y Sinaloa, New Spain), then paralleled the modern Mexico/California border, crossing the Colorado River at its confluence with the Gila River. This was in the domain of the Yuma tribe, with which he established good relations. Anza reached Mission San Gabriel Arcángel, near the California coast, on March 22, 1774, and Monterey, California, Alta California's capital, on April 19. He returned to Tubac by late May, 1774. This expedition was closely watched by Viceroy and King, and on October 2, 1774, Anza was promoted to the rank of lieutenant-colonel, and ordered to lead a group of colonists to Alta California. The Spanish were desirous of reinforcing their presence in Alta California as a buffer against Russian colonization of the Americas advancing from the north, and possibly establish a harbor that would give shelter to Spanish ships. The expedition got under way on October 23, 1775, and arrived at Mission San Gabriel Arcángel in January, 1776, the colonists having suffered greatly from the winter weather en route. Today this route is marked as the Juan Bautista de Anza National Historic Trail. The expedition continued on to Monterey with the colonists. Having fulfilled his mission from the Viceroy, he continued on with Father Pedro Font and a party of twelve others exploring north and found an inland route to the San Francisco Bay described by Portolà. In Anza's diary on March 25, 1776, he states that he "arrived at the arroyo of San Joseph Cupertino (now Stevens Creek), which is useful only for travelers. Here we halted for the night, having come eight leagues in seven and a half hours. From this place we have seen at our right the estuary which runs from the port of San Francisco." Pressing on, Anza located the sites for the Presidio of San Francisco and Mission San Francisco de Asis in present-day San Francisco, California on March 28, 1776.