On the next day, the 28th of September, the provisional Junta met, and declared itself installed under the presidency of Yturbide. Its thirty-eight members accepted by oath the Plan of Iguala and the Treaty of Cordova, and further issued an Act of Independence of the Mexican Empire, subscribed to by all the Junta. A government was formed, called the Regency, composed of Don Agustin de Yturbide, president, and five other members, among them Don Juan O'Donojú. The latter died the next month, and thus ended his very brief career in Mexico; his place was taken by the Bishop of Puebla.
Thus was formed, at a stroke, the Mexican Empire, whose wide territory extended from Guatemala on the south, over lands now included in Texas, the two Californias, and New Mexico at the north.
Many Spaniards, disgusted with this turn of affairs, returned to Europe with their families. Others concluded to accept the situation, and remained to watch the course of events.
The new government set to work in good earnest to strengthen its foundations and extend its influence. The province of Chiapas, on the Pacific coast, declared its emancipation from Spain, and of its own accord withdrew from Guatemala and incorporated itself with Mexico. It still remains a Mexican state. Guatemala also declared its wish to join the Mexican Empire, and the Guatemalian representatives accordingly took their seats in the first Mexican Congress; but the next year this province concluded to become an independent nation on its own account, and took itself away from the empire.
The solemn installation of this second Mexican Congress took place in February, 1822. Its first act was to interfere with the proceedings of the Regency. Ill-feeling, produced by want of harmony, increased daily, forming parties which strongly adhered either to one side or the other. Of these, the original Independents, and such Spaniards as sincerely desired the fulfilment of the Plan of Iguala, by which a Spanish prince was to be chosen their ruler, manifested more and more their disapproval of the President of the Regency; while the other party, composed of the army, the clergy, and some Spaniards, had already accepted the idea of elevating Yturbide to a throne.
A ferment of discordant opinions, conflicting interests, and personal ambitions arose, in the midst of which came the news, naturally to be expected, that the Cortés of Spain declared null and void the Treaty of Cordova, concerted by Yturbide and O'Donojú.
This gave Yturbide his opportunity. On the night of the 18th of May, a movement was begun by a sergeant of one of the regiments, echoed immediately by various garrison corps, proclaiming Yturbide Emperor. The leader modestly referred these applicants to the decision of Congress, and this body, the next day, with soldiers all around, in the highest state of impatient excitement, declared, by a vote of sixty-seven against a minority of fifteen, the Emperor, under the title of Agustin I.
Thus by rapid steps had Yturbide climbed from the position of a simple soldier without rank to the throne of the Montezumas. Wholly different from Morelos, he cannot be called a patriot in the highest sense. Probably his motive from the very beginning was personal ambition, in which loyalty to a king or to a cause had no part. He too, doubtless, had watched the career of Napoleon Bonaparte, at that time a dangerous light shining in the eyes of all men. Yet it must not be forgotten that if Yturbide worked for himself, he yet achieved, at the same time, the independence of his country. His throne was an unsteady one, but the dais erected for it to rest upon became the solid platform of liberty.
Agustin I. took the oath of office before the Mexican Congress, which proceeded to pass decrees establishing the succession to the throne, the titles and forms of address to be held toward the members of the imperial family, as well as their endowments, corresponding to their rank, details which turned out to be of no permanent value.
On the 21st of July, Yturbide and his wife were anointed and crowned in the Cathedral, with all the solemnities and forms which have been observed in Europe on such occasions for centuries.