The Joaquín Band: The History Behind the Legend - Hardcoverby Lori Lee Wilson (Author) After the U. S. Mexican War, gold was discovered in northern California, a Mexican territory that had been ceded to the United States. Thousands of Mexican and American citizens traveled to the gold region and soon clashed. The ruling Americans enforced unjust laws that impelled some Mexicans to become bandits, Joaqun Murrieta among them. He became something of a media myth, with a few newspaper editors complaining that he