While stationed in the town of Iguala, Iturbide proclaims three principles, or "guarantees," for Mexican independence from Spain: Mexico will be an independent monarchy governed by a transplanted King Ferdinand or some other conservative European prince, criollos and peninsulares will henceforth enjoy equal rights and privileges, and the Roman Catholic Church will retain its privileges and religious monopoly.

After convincing his troops to accept the principles, which are promulgated on February 24, 1821, as the Plan of Iguala, Iturbide persuades Guerrero to join his forces in support of the new conservative manifestation of the independence movement.

A new army, the Army of the Three Guarantees, is now placed under Iturbide's command to enforce the Plan of Iguala.

The plan is so broadly based that it pleases both patriots and loyalists.

The goal of independence and the protection of Roman Catholicism brings together all factions.