May Revolution
The mutiny of Aranjuez in 1808 led King Charles IV of Spain to abdicate in favor of his son, Ferdinand VII. Charles IV requested that Napoleon restore him to the throne; instead, Napoleon crowned his own brother, Joseph Bonaparte, as the new Spanish King. These events are known as the Abdications of Bayonne. Joseph's coronation was met with severe resistance in Spain, which started the Peninsular War, and the Supreme Central Junta took power in the name of the absent king. This also led to Spain switching allegiances from France to Britain. France eventually invaded Sevilla, and a Council of Regency based in Cadiz replaced the disbanded Supreme Central Junta.
May Revolution
On May 14, 1810, the British war schooner HMS "Mistletoe" arrived at Buenos Aires with European newspapers that reported the dissolution of the Supreme Central Junta the previous January. The city of Seville had been invaded by French armies, which were already dominating most of the Iberian Peninsula. The newspapers reported that some of the former members of the Junta had taken refuge on the Isla de León in Cadiz. This was confirmed in Buenos Aires on May 17, when the British frigate HMS "John Paris" arrived in Montevideo; the most recent newspapers reported that members of the Supreme Central Junta had been dismissed. The Council of Regency of Cadiz was not seen as a successor of the Spanish resistance but as an attempt to restore absolutism in Spain. The Supreme Central Junta was seen as sympathetic to the new ideas. South American patriots feared both a complete French victory in the peninsula and an absolutist restoration. Cisneros monitored the British warships and seized their newspapers, to conceal the news, but a newspaper came into the hands of Belgrano and Castelli. They spread the news among other patriots and challenged the legitimacy of the Viceroy, who had been appointed by the fallen junta. When Cornelio Saavedra, head of the regiment of Patricians, was informed of this news, he decided that it was finally the ideal time to take action against Cisneros. Martín Rodríguez proposed to overthrow the Viceroy by force, but Castelli and Saavedra rejected this idea and proposed the convening of an open cabildo.