Aborigines have lived in central Australia for at least 20,000 years, although few details of their history are known. The Aranda were nomadic hunters and gatherers when Whites first came to Central Australia in the 1860s, but from the 1870s onward they steadily moved into a more sedentary (though still mobile) way of life on missions, pastoral stations, and government settlements. Relations between Aranda groups and between Aranda groups and their neighbors (mostly Western Desert people) have varied from friendship, alliance, and intermarriage, on the one hand, to enmity and hostility on the other. Relations with European interests have also varied greatly over the years, ranging from guerrilla warfare and cattle stealing to enforced or voluntary settlement and work on missions and cattle stations. European attitudes and practices towards Aranda people have also varied greatly—from tolerance to bigotry, from laissez-faire to paternalism, and from protectionism to murder. Since World War II, when development in central Australia greatly increased, the Aranda have lived through the official government policy of assimilation. They are now experiencing the effects of the relatively new policy of self-determination, which has caused their lives to be increasingly affected by Aboriginal bureaucracies.