In the Winter of 1845 -- 46, the federally commissioned explorer John C. Frémont and a group of armed men appeared in Alta California. After telling the Mexican governor and the American Consul Larkin he was merely buying supplies on the way to Oregon, he instead went to the populated area of California and visited Santa Cruz and the Salinas Valley, explaining he had been looking for a seaside home for his mother. Mexican authorities became alarmed and ordered him to leave. Frémont responded by building a fort on Gavilan Peak and raising the American flag. Larkin sent word that Frémont 's actions were counterproductive. Frémont left California in March but returned to California and took control of the California Battalion following the outbreak of the Bear Flag Revolt in Sonoma.
who led the american forces that helped seize california from mexico
the federally commissioned explorer John C. Frémont