Many flags have flown over California soil A few are: the Spanish Empire’s royal standard of Carlos V  the Mexican Republic’s banner of green  white and red vertical bars  the Flag of Argentina hoisted by revolutionary (some say pirate) Hippolyte de Bouchard for sixteen days in 1818  the flags of Russia and the Russian-American Company 1812-1841 at today’s Fort Ross  and the Bear Flag for three weeks in 1846 until it was supplanted by the Flag of the United States