In the early months of 1820, Portugal was engulfed in a wave of liberal sentiment, spurred by the outcomes of the French Revolution and the growing popularity of constitutional governance throughout Europe. In Oporto, a group of military officers, influenced by these liberal ideals, instigated an uprising on 24 August to demand a constitutional government. The insurrection was not solely a reflection of military discontent; it harnessed widespread public support from citizens who desired reform and modernization of the political structure, moving away from the entrenched absolutism of King John VI.

The insurrection resulted in the proclamation of a temporary constitution, which sought to limit the powers of the monarchy and establish the sovereignty of the nation under a constitutional framework. This moment illustrated the fervent desire for change within Portuguese society, as supporters included not only soldiers but also educated members of the bourgeoisie who had borne witness to the successes of similar revolutionary movements elsewhere.

The insurrection eventually led to the establishment of the Liberal Constitution of 1822, though not without subsequent challenges. The insurrection sparked a series of escalating tensions within the country as conservative royalists opposed these reforms, resulting in civil unrest and further revolutionary actions in the years to follow. The Constitutionalists' initial success set the stage for future conflicts in the quest for democratic governance in Portugal.