Mexico Europeans. In 1521, the Spanish Empire conquered and colonized the territory from its politically powerful base in Mexico-Tenochtitlan (part of Mexico City), which was administered as the viceroyalty of New Spain. Three centuries later, the territory became a nation state following its recognition in 1821 after the colony's Mexican War of Independence. The post-independence period was tumultuous, characterized by economic inequality and many contrasting political changes. The Mexican–American War (1846–1848) led to a territorial cession of the extant northern territories to the United States. The Pastry War, the Franco-Mexican War, a civil war, two empires, and the Porfiriato occurred in
Mexican–American War could not be released from its obligations. The US was released from all obligations of Article XI five years later by Article II of the Gadsden Purchase of 1853. The 1848 Treaty of Guadalupe Hidalgo ended the war and enforced the Mexican Cession of the northern territories of Alta California and Santa Fe de Nuevo México to the United States. Mexico acknowledged the loss of what became the State of Texas and accepted the Rio Grande as its northern border with the U.S. The losses amounted to one-third of its original territory from its 1821 independence. Before the secession of