 In that role he was the principal implementor of the Spanish Crown's pacification program in the region of Zacatecas, northern Jalisco and San Luis Potosí.Caldera was instrumental in the migration of 400 Tlaxcaltec families in 1591 to the newly pacified region to help Christianize the local indigenous populations and consolidate the peace.The consolidation of peace during his tenure facilitated settlement of the region and the eventual Spanish occupation of what would, two and a half centuries later, become the American Southwest.