Mexican War of Independence arm of the conspirators and in early 1821 he met Vicente Guerrero. Both proclaimed the Plan of Iguala, which called for the union of all insurgent factions and was supported by both the aristocracy and clergy of New Spain. It called for monarchy in an independent Mexico. Finally, the independence of Mexico was achieved on September 27, 1821. After that, the mainland of New Spain was organized as the Mexican Empire. This ephemeral Catholic monarchy changed to a federal republic in 1823, due to internal conflicts and the separation of Central America from Mexico. After some Spanish reconquest attempts, including
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