Mexico also contended with indigenous groups which controlled territory that Mexico claimed in the north.  The Comanche controlled a huge territory in the sparsely populated region of central and northern Texas. Wanting to stabilize and develop the frontier, the Mexican government encouraged Anglo-American immigration into present-day Texas. The region bordered the United States, and was territory controlled by Comanches. There were few settlers from central Mexico moving to this remote and hostile territory. Mexico by law was a Catholic country; the Anglo Americans were primarily Protestant English speakers from the southern United States. Some brought their black slaves, which after 1829 was contrary to Mexican law. Santa Anna sought to centralize government rule, suspending the constitution and promulgating the Seven Laws, which place power in his hands. When he suspended the 1824 Constitution, civil war spread across the country. Three new governments declared independence: the Republic of Texas, the Republic of the Rio Grande and the Republic of Yucatán.