The acquisition of former Mexican territories by the United States in the aftermath of the Mexican–American War initiated a period of economic uncertainty and dislocation among many former Mexicans in what was now their new country. When the war ended, those Mexicans living in the United States became U.S. citizens and their property rights were supposed to be guaranteed by provisions of the Treaty of Guadalupe Hidalgo which ended the war. However, these protections were not always upheld. The result was that many Mexican Americans lost their land and economic livelihood in the later years of the 1800s as waves of new settlers from the Eastern United States moved into Texas, California, and the Southwest.