The May Revolution (Spanish: Revolución de Mayo) was a series of revolutionary political and social events that took place during the early nineteenth century in the city of Buenos Aires, capital of the Viceroyalty of the Río de la Plata, a colony of the Spanish Crown which at the time contained the present-day nations of Argentina, Bolivia, Paraguay and Uruguay. The consequence of the revolution was that the head of the Viceroyalty, Viceroy Cisneros, was ousted from office, and role of government was assumed by the Primera Junta. There are many reasons, both local and international, that promoted such developments.
The United States had emancipated themselves from the Kingdom of Great Britain in 1776, which provided a tangible example that led Criollos to believe that revolution and independence from Spain could be realistic aims. In the time between 1775 and 1783 the Thirteen Colonies started the American Revolution, first rejecting the governance of the Parliament of Great Britain, and later the British monarchy itself, and waged the American Revolutionary War against their former rulers. The changes were not only political, but also intellectual and social, combining both a strong government with personal liberties. The text of the Declaration of Independence stated that all men are created equal (and thus become equal before the law), and had unalienable rights to life, liberty and the pursuit of happiness. They had also chosen a republican form of government, instead of keeping a monarchic one. Even more, the fact that Spain aided the colonies in their struggle against Britain weakened the argument that ending allegiance to the mother country could be considered a crime.