named it Rio de los Sacramentos, or "River of the Blessed Sacrament". In the following years, two more Spanish expeditions traversed the lower part of the river, the last one in 1817. The next visitors were Hudson's Bay Company (HBC) fur trappers exploring southwards from the disputed Oregon Country, starting in the 1820s. The first organized expedition, led by Peter Skene Ogden, arrived in the area of Mount Shasta in 1826. By this time, California was under the control of Mexico, although few Mexican settlers had come to what would later become the state, mostly settling in the small pueblos and ranchos along the south and central coast. The HBC mountain men created the Siskiyou Trail out of several Native American paths that ran through the mountains between Oregon's Willamette Valley and the northern part of the Sacramento Valley. In the years to come, this path, which eventually extended from San Francisco to Portland, Oregon following parts of the Sacramento, Willamette, Klamath, Rogue, and other rivers would become an important trade and travel route. Gold Rush Although just one of thousands of American emigrants that poured into California over the next few years when California became part of the United States, John Augustus Sutter's arrival marked a turning point in the history of the Sacramento Valley, and California as a whole. In 1841, Sutter and his men built a fortress at the confluence of the Sacramento and American Rivers and the Mexican government granted him almost of land surrounding the two rivers. Naming it New Helvetia, he created an agricultural empire in the lower Sacramento Valley, attracting several hundred settlers to the area, and relied on Native American labor to maintain his domain. Sutter had something of a two-faced relationship with the many Native American groups in the area. He was friendly with some of the tribes, and paid their leaders handsomely for supplying workers, but others he seized by force to labor in the fields. After the Bear Flag Revolt of 1846 and the Mexican–American War, in which California became part of the United States, Sutter and other large landholders in California held on to their properties. In 1848 Sutter assigned James W. Marshall to build a sawmill on the South Fork American River at Coloma, where Marshall discovered gold. Although Sutter and Marshall originally intended to keep the find a secret, news soon broke attracting three hundred thousand