Memories With Out Borders
In 1846, the United States invaded and conquered California, then part of the Republic of Mexico. This event, one aspect of the 1846-1848 U.S.-Mexican War, led to U.S. annexation of California through the 1848 Treaty of Guadalupe Hidalgo. Mexican American history in California had begun.
http://www.nps.gov/history/history/online_books/5views/5views5.htm
