Abdications of Bayonne in the context of "Peninsular War"

Bonapartist Spain was a Napoleonic client state established in 1808 after Napoleon, who had stationed his Imperial Army in Spain under the pretense of a joint Franco–Spanish invasion of Portugal, forced the ruling Spanish Bourbons to abdicate, and installed his brother, Joseph Bonaparte on the Spanish throne, which ignited a people's revolt by Spanish citizens and led to the Peninsular War, where France was defeated and forced to retreat from Spain.

The kingdom was officially known as Kingdom of (the) Spain(s) and (the) Indies, with "the Indies" referring to the East and West Indies as well as Spain's colonial possessions more broadly. It never managed to exert control over these territories however, not only did the French invasion weaken Spain's grasp on its overseas empire, kickstarting the Spanish American wars of independence, but even on the Spanish mainland, the House of Bonaparte's grip was tenuous. Large parts of the country came under the control of juntas, which remained loyal to Ferdinand VII and the old Bourbon kingdom, allying with the Coalition forces of Britain and Portugal to undermine the French occupation.

The May Revolution (Spanish: Revolución de Mayo) was a week-long series of events that took place from 18 to 25 May 1810, in Buenos Aires, capital of the Viceroyalty of the Río de la Plata. This Spanish colony included roughly the territories of present-day Argentina, Bolivia, Paraguay, Uruguay, and parts of Brazil. The result was the removal of Viceroy Baltasar Hidalgo de Cisneros and the establishment of a local government, the Primera Junta (First Junta), on 25 May.

The May Revolution was a direct reaction to Napoleon's invasion of Spain. In 1808, King Ferdinand VII abdicated in favour 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 1 February 1810, French troops took Seville and gained control of most of Andalusia. The Supreme Junta retreated to Cádiz, formed the Council of Regency of Spain and the Indies to govern, and dissolved itself. News of these events arrived in Buenos Aires on 18 May, brought by British ships.