Key Facts
- Duration
- 1821–1823 (approx. 2 years)
- Peak area
- ~4,925,283 km²
- Peak population
- ~6.5 million
- Sole emperor
- Agustín I (Agustín de Iturbide)
- Founding document
- Plan of Iguala, 1821
Imperial Zenith Metrics
Territorial Scale Comparison
Peak area vs modern sovereign states
Historical Trajectory
Phase I: Rise
Agustín de Iturbide, a former Royal Spanish military officer, unified independence forces under the Plan of Iguala in 1821, which envisioned an independent Mexican monarchy. After the last Spanish viceroy signed the Treaty of Córdoba in September 1821, Mexico achieved independence. With no European royal willing to assume the throne, public demonstrations in May 1822 pressed Iturbide to become emperor, and Congress approved his coronation as Agustín I in July 1822.
Phase II: Zenith
At its height, the empire encompassed a vast territory stretching from modern Mexico through Central America, covering nearly 4.9 million km² and a population of approximately 6.5 million. As the first independent government of Mexico and the only post-independence monarchy among former Spanish viceroyalties, the empire sought to establish constitutional governance, though it faced chronic fiscal insolvency from its inception.
Phase III: Decline
Disputes between Iturbide and Congress over legitimacy and finances escalated until October 1822, when he dissolved Congress and replaced it with a loyalist junta. By December 1822 the Mexican Army rebelled in favor of restoring democratic rule. Unable to suppress the revolt, Iturbide reconvened Congress in March 1823 and abdicated. A republican provisional government assumed power, abolished the monarchy, and laid the groundwork for the First Mexican Republic.
Notable Imperial Reigns
Selected rulers mapping the empire’s trajectory