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
The United States' declaration of independence from Great Britain in 1776 led criollos (Spanish peoples born in the Americas) to believe that revolution and independence from Spain were feasible. Between 1775 and 1783, the American patriots of the Thirteen Colonies waged the American Revolutionary War against both the local loyalists and the Kingdom of Great Britain, eventually establishing a popular government in the place of the British monarchy. The fact that Spain aided the colonies in their struggle against Britain weakened the idea that it would be a crime to end one's allegiance to the parent state.