The sense of Chicano nationalism was enhanced by a geographical proximity of the United States and Mexico. Chicanos use the name Aztlán in reference to territories within the boundaries of the Mexican Cession, the land that was "granted" to Spain in 1493 by Pope Alexander VI in Bull Inter caetera, then claimed by the First Mexican Empire in 1821 when Spain signed the Treaty of Córdoba at the conclusion of the Mexican War of Independence, then claimed as "territories" (as opposed to "states", often referred to as "provinces") by 1824 Constitution, and finally ceded to the United States in 1848 as an outcome of the Treaty of Guadalupe Hidalgo (although it also included Texas, which had earlier proclaimed its independence from the government in Mexico City and was independent territory.)