Arizona was admitted to the Union on February 14, 1912. It was the 48th and the last of the conterminous states to be admitted to the Union. Arizona was ruled by Spain and Mexico before it became a part of the United States. Before the advent of the Europeans, Arizona was the abode of different Native American tribes. In the 1500s the area came under the control of the Spanish government. During their rule in the region, the Spanish founded fortified towns at Tubac in 1752 and Tucson in 1775. With the independence of Mexico from Spain in 1821, the territory that is now Arizona became a part of Nueva California, also called Alta California. Originally a part of New Mexico, in 1848 the territory was ceded to the United States. In 1863, it became a separate territory. On February 14, 1912 it was admitted to the Union as the 48th state.