May Revolution
The May Revolution was a direct reaction to Spain's Peninsular War. In 1808, King Ferdinand VII of Spain abdicated in favor of Napoleon, who granted the throne to his brother, Joseph Bonaparte. A Supreme Central Junta led resistance to Joseph's government and the French occupation of Spain, but eventually suffered a series of reversals that resulted in the Spanish loss of the northern half of the country. On February 1, 1810, French troops took Seville and gained control of most of Andalusia. The Supreme Junta retreated to Cadiz and dissolved itself, and the Council of Regency of Spain and the Indies replaced it. News of these events arrived in Buenos Aires on May 18, brought by British ships.
May Revolution
Martín de Álzaga began a mutiny to remove Liniers. On January 1, 1809, an open cabildo (an extraordinary meeting of "vecinos", prominent people of the city) chaired by Álzaga demanded the resignation of Liniers and the appointment of a local junta. The Spanish militia and a group of people summoned by the meeting gathered to support the rebellion. A small number of criollos, notably Mariano Moreno, supported the mutiny, but most of them did not. They felt that Álzaga wanted to remove the Viceroy to avoid his political authority while keeping the social differences between criollos and peninsulars unchanged. The riot was quickly routed when criollo militias led by Cornelio Saavedra surrounded the plaza and dispersed the insurgents. As a result of the failed mutiny, the rebel militias were disarmed. This included all peninsular militias, and the power of the criollos increased as a result. The leaders of the plot, with the exception of Moreno, were exiled to Carmen de Patagones. Javier de Elío freed them and gave them political asylum at Montevideo.