As a nationalistic concept, frontier refers to America's westward expansion, which was propelled in the nineteenth century by Manifest Destiny. Culturally, frontier promises even more: the creation of communities, the development of markets and states, the merging of peoples and cultures, and the promise of survival and persistence based on values of equality and democracy. Thousands of people left their homes in the East to pursue these ideals, including large communities of African Americans. However, African Americans, like many other cultural groups who moved westward, encountered struggles when they reached the new frontier. In some cases, they faced the same problems they left the East to escape. As new frontier territories and states were founded, new regional policies on slavery were also created. When the Treaty of Guadalupe Hidalgo (1848) ceded the territories of California and New Mexico to the United States, it outlawed slavery in the new territories. California entered the Union in 1850 as an officially free state. Before the Civil War, about one thousand slaves lived in California, which despite its status as a free state remained inconsistent in defining its anti-slavery laws. The state continued to label as "property" both fugitive slaves and those who entered the state with their masters before 1850. As a result, de facto slavery continued in California. The state had the largest number of bondservants west of Texas, working in fields and households.