Baltasar Hidalgo de Cisneros
The news of the fall of the Junta of Seville reached Buenos Aires in May 1810. With both the king of Spain and the Junta removed of power, many people thought that Cisneros had no legitimacy to govern, starting the May Revolution. Cisneros tried to calm down the population, to no avail. He called the commanders of the local armies and requested their support, but they denied it. Cisneros was ultimately forced to allow an open cabildo, which would discuss what to do. Although those meetings were usually composed of the wealthiest population, the army and a group of rioters plotted to prevent the entry of many wealthy people and allow common people instead.
Juan José Castelli
When the news of the fall of the Junta of Seville arrived, the group headed by Castelli and Belgrano led the process leading to the May Revolution. Castelli and Saavedra were the most important leaders of the time, and first discarded Martín Rodríguez's plan to expel Cisneros in a coup d'état. After several discussions, they decided to request an open cabildo, an emergency popular assembly. Castelli and Belgrano negotiated with the senior alcalde and nobleman, Juan de Lezica, and the procurator, Julián de Leiva. Although they convinced them, they still needed the permission of Cisneros himself, for which Castelli and Rodriguez went to his office at the Fort of Buenos Aires. Previously, Cornelio Saavedra had denied Cisneros the support of the Regiment of Patricians, on the premise that with the disappearance of the Junta of Seville—who had appointed him as viceroy—he no longer had the right to hold that position.