Once the independence of Mexican Empire was declared, Agustín de Iturbide was designated President of the Regency; because of his great popularity and prestige, the Interim Board gave him full authority. Elections for the Constituent Congress took place in December 1821 and in January 1822. There is no accurate record of how many deputies were elected, but it has been estimated at about 126, plus 52 given to Guatemala, Honduras, Nicaragua, Chiapas, former captaincies which also agreed to the Plan of Iguala.