An open cabildo (extraordinary town council meeting) was held in Buenos Aires amid Spain’s dynastic crisis, providing the political mechanism that enabled local elites to debate and move toward replacing the viceroy’s authority.
The May Revolution culminated in the formation of the Primera Junta in Buenos Aires, replacing Viceroy Baltasar Hidalgo de Cisneros and launching revolutionary governance over the former viceroyalty.
Provincial delegates were incorporated into the Buenos Aires junta, creating the Junta Grande—an early attempt to broaden political representation beyond the capital while retaining a central executive.
After political crisis within the revolutionary leadership, executive power shifted to the First Triumvirate, marking another institutional reorganization of the revolutionary state.
A political upheaval in Buenos Aires replaced the First Triumvirate with the Second Triumvirate, which soon called a constituent assembly to reshape the revolutionary government.
The Assembly of the Year XIII opened in Buenos Aires, pursuing sovereignty-focused reforms and institutional changes (even though it did not achieve a full constitution or a formal declaration of independence at the time).
The Assembly concentrated executive authority in a single office—Supreme Director—and appointed Gervasio Antonio de Posadas as the first holder, signaling a more centralized (unitary-leaning) state structure.
The capitulation of Montevideo removed a major royalist stronghold in the Río de la Plata region, strengthening the revolutionary position and reshaping control over the estuary.
The Mutiny of Fontezuelas triggered the collapse of Carlos María de Alvear’s brief Supreme Directorship, underscoring the instability of central authority and accelerating political reconfiguration.
Delegates meeting at the Congress of Tucumán declared independence from Spain, a foundational act for the revolutionary state and its claims to international legitimacy.
The independence congress moved from Tucumán to Buenos Aires, reflecting ongoing tensions over centralization and the practical pull of the port-city’s political and administrative resources.
The Constitution of 1819 was promulgated by the congress but faced immediate provincial rejection, deepening conflict between centralists and federalists and weakening national cohesion.
Federalist forces defeated the central government’s army at Cepeda, precipitating the fall of the Supreme Directorship, the repeal of the 1819 constitution, and the onset of the Anarchy of the Year XX.
Buenos Aires, Santa Fe, and Entre Ríos signed the Treaty of Pilar, widely treated as a foundational pact for subsequent federal organization by ending immediate hostilities and affirming provincial autonomy.
During renewed efforts at national organization amid the Cisplatine War, Congress selected Bernardino Rivadavia as president—an important (and contested) step toward a centralized executive at the national level.
Chile and the United Provinces signed a friendship and alliance treaty intended to formalize post-emancipation relations; it ultimately did not enter into force because it was not ratified by Chile.
United Provinces of the Río de la Plata (1810–1826)
