August 24, 1821

Treaty of Córdoba

Iturbide and O'Donojú sign the Treaty of Córdoba

Spain's newest chief of New Spain signed an independence settlement knowing Madrid had never authorized him to do it — and one small clause he accepted helped make a Mexican general's imperial throne possible.

24 August 1821: duplicate originals at Córdoba

On 24 August 1821, Agustín de Iturbide, commander of the Army of the Three Guarantees, met Juan O'Donojú, Spain's newly arrived captain general of New Spain, in the town of Córdoba, Veracruz. They signed the seventeen-article Treaty of Córdoba in duplicate, each keeping an original.

Article 1 declared the former New Spain a sovereign, independent nation: the Mexican Empire. O'Donojú signed knowing he had no authorization from Madrid to recognize any such thing — he judged, correctly, that Spanish authority could not recover a territory whose capital his opponents were besieging.

The clause that changed everything

The treaty broadly followed Iturbide's Plan of Iguala — constitutional monarchy, throne offered first to Ferdinand VII and then to named Bourbon princes — but with one crucial modification. Where Iguala required a monarch from a reigning European house, Article 3 allowed the Mexican Cortes to choose anyone at all if the Bourbons declined.

That small opening helped make Iturbide's own elevation possible: after Spain repudiated the arrangement, he was acclaimed by troops and crowds on 18 May 1822 and chosen emperor by Congress the next day.

What the signatures actually bought

In Article 17, O'Donojú undertook to secure the bloodless withdrawal of the Spanish troops still holding Mexico City. He subsequently helped overcome royalist resistance, and the arrangement was carried out: the garrison marched out on 21–22 September, the Army of the Three Guarantees entered on the 27th, and the Act of Independence followed a day later.

Spain's Cortes declared the treaty null in February 1822, precisely because O'Donojú had lacked authority — Madrid neither granted nor recognized Mexico's independence. Whether the treaty legally created that independence or formalized one already won in fact remains a debated constitutional question. Iturbide's own empire lasted barely ten months; he abdicated in March 1823.

Sources

Researched 24 Aug 2026 5 sources 1 audit pass

How this was checked

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What the sources leave uncertain

The signing and date are secure; the treaty’s legal effect is the disputed issue.
O’Donojú represented the Spanish constitutional government as captain general and superior political chief, but he was not authorized to recognize the loss of New Spain.
Spain rejected the treaty and did not recognize Mexican independence until a later bilateral settlement.
The treaty confirmed much of the Plan of Iguala but also altered it, especially by allowing the Mexican Cortes to choose an emperor after the named princes refused.