In the early sixteenth century the Mixteca was divided into numerous small kingdoms, or cacicazgos , ruled over by a hereditary elite. The Mixtec elite also ruled over non-Mixtec-speaking peoples, and some Mixtec kingdoms had, in turn, been conquered by the Central Mexican Triple Alliance. The Mixtec elite, related to one another by marriage and descent, patronized one of the finest artistic traditions in the New World. The area was conquered by the Spanish between 1522 and 1524. Owing to severe population decline in the wake of the sixteenth-century plagues, as well as to the region's lack of major mineral and agricultural resources, relatively few Spaniards settled in the area, however, and the pressures for change, although substantial, were not as great as in other areas in Mesoamerica. In the nineteenth and twentieth centuries outsiders began to move into the Mixteca in increasing numbers, and commercial agriculture was expanded. At the same time, the region became a center for several armed political movements, and Mixtec-speaking peoples actively participated in the struggle for independence, as well as in the Wars of the Reform and the Mexican Revolution of 1910-1920. Today, most Mixtec speakers are what anthropologists call peasants, but there is a growing Mixtec middle class, made up of teachers, government workers, technicians, politicians, health officials, and other professionals.