Friday, May 18 and Saturday, May 19
Although Viceroy Cisneros attempted to conceal the news of the Spanish defeat, the rumor had already spread throughout Buenos Aires. Most of the population was uneasy; there was high activity at the barracks and in the Plaza, and most shops were closed. The "Café de Catalanes" and the "Fonda de las Naciones", frequent criollo meeting places, became venues for political discussions and radical proclamations; Francisco José Planes shouted that Cisneros should be hanged in the Plaza as retribution for the execution of the leaders of the ill-fated La Paz revolution. People who sympathized with the absolutist government were harassed, but the fights were of little consequence because nobody was allowed to take muskets or swords out of the barracks.
The Viceroy, trying to calm the criollos, gave his own version of events in a proclamation. He asked for allegiance to King Ferdinand VII, but popular unrest continued to intensify. He was aware of the news, but only said that the situation on the Iberian Peninsula was delicate; he did not confirm the fall of the Junta. His proposal was to make a government body that would rule on behalf of Ferdinand VII, together with Viceroy of Peru José Fernando de Abascal y Sousa, Governor of Potosí Francisco de Paula Sanz and President of the Royal Audiencia of Charcas Vicente Nieto.
Not fooled by the Viceroy's communiqué, some criollos met at the houses of Nicolás Rodríguez Peña and Martín Rodríguez. During these secret meetings, they appointed a representative commission composed of Juan José Castelli and Martín Rodríguez to request that Cisneros convene an open cabildo to decide the future of the Viceroyalty.
During the night of May 19 there were further discussions at Rodríguez Peña's house. Saavedra, called by Viamonte, joined the meeting, which involved military and civilian leaders. They arranged that Belgrano and Saavedra would meet with Juan José de Lezica, the senior alcalde (municipal magistrate), while Castelli would meet with the procurator Julián de Leiva, to ask for their support. They asked the Viceroy to allow an open cabildo, and said that if it was not freely granted the people and the criollo troops would march to the Plaza, force the Viceroy to resign by any means necessary, and replace him with a patriot government. Saavedra commented to Lezica that he was suspected of betrayal because of his constant requests for cautious and measured steps. This comment was designed to pressure Lezica into speeding up the legal system to allow the people to express themselves, or otherwise risk a major rebellion. Lezica asked for patience and time to persuade the Viceroy, and leave a massive demonstration as a last resort. He argued that if the Viceroy was deposed in that way, it would constitute a rebellion, which would turn the revolutionaries into outlaws. Manuel Belgrano gave the following Monday as the deadline to confirm the open cabildo before taking direct action. Leiva would later act as a mediator, being both a confidante of Cisneros and a trusted negotiator for the more moderate revolutionaries.
Read more about this topic: May Revolution, May Week