Jalisco, where Spanish conquistadores first distilled tequila in 1600, around Amatitan and the nearby town of Tequila, once supplied almost all the industry's blue agave. For tequila to bear the Mexican government's denomination of origin, it must be distilled only from blue agave grown in Jalisco or in scattered areas in four other states. The three giant companies that dominate production José Cuervo, Herradura and Sauza have in recent years been moving to those outlying areas, planting their own agave fields or striking deals with farmers to assure supplies of blue agave.