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.
Eustaquio Díaz Vélez
Díaz Vélez had good relations with the conspirators who, before 1810, sought to achieve the independence of his country. He actively supported the May Revolution, participating in the meetings that decided the dismissal of Viceroy Baltasar Hidalgo de Cisneros, attending the one of May 19, called by Nicolás Rodríguez Peña. On the occasion of the Open cabildo of May 22, Colonel Cornelio Saavedra appointed him as head of the Patricians guards that enabled the assembly meeting that expressed the will of the people.