Plan of Iguala in the context of "Agustin Iturbide"

The Mexican Empire (Spanish: Imperio Mexicano, pronounced [imˈpeɾjo mexiˈkano] ) was a constitutional monarchy and the first independent government of Mexico. It was also the only former viceroyalty of the Spanish Empire to establish a monarchy after gaining independence. The empire existed from 1821 to 1823, making it one of the few modern-era independent monarchies in the Americas. To distinguish it from the later Second Mexican Empire (1864–1867) under Emperor Maximilian, this historical period is commonly referred to as the First Mexican Empire. The empire was led by former Royal Spanish military officer Agustín de Iturbide, who ruled as Agustín I.

The establishment of a monarchy was the initial goal for an independent Mexico, as outlined in the Plan of Iguala, a political document drafted by Iturbide that unified the forces fighting for independence from Spain. Following the signing of the Treaty of Córdoba by the last Spanish viceroy in September 1821, the plan for a Mexican monarchy advanced. Iturbide's popularity reached its peak on May 18, 1822, when public demonstrations called for him to become emperor in the absence of a European royal willing to assume the throne. The Mexican Congress approved the proposal, and Iturbide was crowned in July 1822.

Monarchism in Mexico is the political ideology that defends the establishment, restoration, and preservation of a monarchical form of government in Mexico. Monarchism was a recurring factor in the decades during and after Mexico's struggle for independence.

Beginning in 1808, it was unclear near the ending of the kingdom of the Viceroyalty of New Spain what form of government—monarchical or republican—might replace the absolutism of Ferdinand VII of Spain, but the default position in that era was monarchy. In 1821, Mexico declared the Independence of the Mexican Empire. However, lacking a prince to ascend the Throne of Mexico, Agustín de Iturbide, a criollo royalist general who made an alliance with the insurgents for independence, was proclaimed president of the Regency. His Plan of Iguala united factions for independence and envisioned a sovereign nation, with the stated hope that new state would be led by a member of the Spanish royal family or a prince from another European royal house.

Agustín Cosme Damián de Iturbide y Arámburu (Spanish pronunciation: [aɣusˈtin de ituɾˈbiðe] ; 27 September 1783 – 19 July 1824), commonly known as Agustín de Iturbide and later by his regnal name Agustín I, was the first Emperor of Mexico from 1822 until his abdication in 1823. An officer in the royal Spanish army, during the Mexican War of Independence he initially fought insurgent forces rebelling against the Spanish crown before changing sides in 1820 and leading a coalition of former royalists and long-time insurgents under his Plan of Iguala. The combined forces under Iturbide brought about Mexican independence in September 1821. After securing the secession of Mexico from Spain, Iturbide was proclaimed president of the Regency in 1821; a year later, he was proclaimed Emperor, reigning from 19 May 1822 to 19 March 1823, when he abdicated. In May 1823 he went into exile in Europe. When he returned to Mexico in July 1824, he was arrested and executed.

The Treaty of Córdoba established Mexican independence from Spain at the conclusion of the Mexican War of Independence. It was signed on August 24, 1821 in Córdoba, Veracruz, Mexico. The signatories were the head of the Army of the Three Guarantees, Agustín de Iturbide, and, acting on behalf of the Spanish government, Jefe Político Superior Juan O'Donojú. The treaty has 17 articles, which developed the proposals of the Plan of Iguala. The Treaty is the first document in which Spanish (without authorization) and Mexican officials accept the liberty of what will become the First Mexican Empire, but it is not today recognized as the foundational moment, since these ideas are often attributed to the Grito de Dolores (September 16, 1810). The treaty was rejected by the Spanish government, publishing this determination in Madrid on February 13 and 14, 1822.

Trinidad Anastasio de Sales Ruiz Bustamante y Oseguera (Spanish pronunciation: [anasˈtasjo βustaˈmante]; 27 July 1780 – 6 February 1853) was a Mexican physician, general, and politician who served as the 4th President of Mexico three times from 1830 to 1832, 1837 to 1839, and 1839 to 1841. He also served as the 2nd Vice President of Mexico from 1829 to 1832 under Presidents Vicente Guerrero, José María Bocanegra, himself, and Melchor Múzquiz. He participated in the Mexican War of Independence initially as a royalist before siding with Agustín de Iturbide and supporting the Plan of Iguala.

Bustamante was a member of the Provisional Government Junta, the first governing body of Mexico. After the fall of the First Mexican Empire, his support for Emperor Iturbide was pardoned by President Guadalupe Victoria. The controversial 1828 general election sparked riots forcing the results to be nullified, as a result, Congress named him vice president while the liberal Vicente Guerrero was named president. Bustamante's command of a military reserve during the Barradas Expedition in 1829 allowed him to launch a coup d'état ousting Guerrero.