 This alliance coalesced towards the end of 1820 behind Agustín de Iturbide, a colonel in the royal army, who at the time was assigned to destroy the guerrilla forces led by Vicente Guerrero.Instead Iturbide entered into negotiations, which resulted in the Plan of Iguala, which would establish New Spain as an independent kingdom, with Ferdinand VII as its king.With the Treaty of Córdoba, the highest Spanish official in Mexico approved the Plan of Iguala, and although the Spanish government never ratified this treaty, it did not have the resources to enforce its rejection.