When the independence of Mexico was achieved, Yucatán also reached its independence and joined the ephemeral Mexican Empire. The Empire was overthrown in 1823, the provinces of the empire became independent and almost immediately Yucatán, Jalisco, Oaxaca and Zacatecas declared themselves free and sovereign states. Yucatán installed its First Congress on August 20, 1823 chaired by José María Quiñones. While Congress was preparing the constitution that would govern Yucatán, was issued a decree which was temporarily adopted the Spanish Constitution of 1812 known as the Constitution of Cádiz. On April 6, 1825 was promulgated the first Constitution of the "Free State" of Yucatán, in which was established that the Republic of Yucatán would be, popular, representative and federated with the Mexican federation.