The May Revolution and War for Independence
The War for Independence can be traced to start with the French Revolutionary Wars. While the causes reached much deeper then that, notably the social conflict between two dominate classes that existed, the Criollos and the Peninsulars and the Spanish monopoly of trade. It would be the French Revolution and the wars that followed that would set the spark that would set in motion for the War of Independence.
When the war of the Second Coalition broke out in 1798, The Vice-royalty of Rio de la Plata would fight on the side of her mother country. It was during this part of the conflict that the British would launch two separate invasions to capture the city Buenos Aires and add it to the growing British Empire. The first invasion would be launched in 1806. When the British took the town of Quilmes near Buenos Aires, this would spook the Vice-royal to flee the city and take the treasury to the city of Cordoba. This allowed the British to capture the city. However, the Spanish would be able to retake the city, though this would be more due to the native Criollos efforts then Madrid's help.
After the liberation of Buenos Aires, the citizens of the city would do the unprecedented step of appoint their own Vice royal by nominating Santiago de Liniers, a Frenchman who sided with the Spanish. Santiago would be approved by king Charles IV. In order to prevent the British from seizing the city again, which they would try again in 1807, the local Criollos would form their own militias for defence.
However, while the British Invasions lead the seeds of revolt, it was the Peninsular War that would set the spark. The French Invasion of Spain deposed the current King of Spain Ferdinand VII(son of king Charles IV) it forced everyone in the colonies to decide whom should they support. It would also lead to the creation of the Juntas throughout the Spanish empire.
The Juntas began in Spain as a way to deal with the Peninsula War, where local communities would organize themselves military for defending the homeland. This would then echo across to the Americas as people from Mexico to Buenos Aires followed in their footsteps. However when the Junta of Seville, which was the largest and most influential Junta in Spain fell to Napoleon's forces this would change things. The government of Spain would be reorganized into the council of Regency. This would be disputed by the people in the Americas.
In Buenos Aires in the month of May, they would call forth a meeting to decide what should be done. This would begin the May Revolution and create the Primera Junta, though the Primera Junta would evolve into the Junta Grande by the end of the year.
While the events of the May Revolution are regarded as the beginning of the war for independence from Spain, it should be noted that the Primera Junta was originally not fighting for independence. It proclaimed itself loyal to King Ferdinand. It did help that while King Ferdinand was a captive of Napoleon, he proclaimed himself to be in favor of liberal enlightenment ideals in contrast to the absolution of his father.
The first campaigns within the Vice-royalty were not about becoming independent but showing that they were the legitimate power in the Vice-royalty. That said the names of the sides are the Royalists favoring the Regency and the Patriots whom sided with the Junta Grande and successive governments. The Junta Grande and the Council of Regency both claimed to be the legitimate authority in Vice-royalty of Rio de la Plata. However, the campaigns first in Upper Peru and then into Paraguay that the Junta Grande undertook turned out to be failures.
This would result in the creation of the First Triumvirate. The Triumvirate would be lead by Feliciano Chiclana, Juan José Paso and Manuel de Sarratea. The Triumvirate would see the fortunes of the war against the royalist though more due to men Manuel Belgrano whom would disregard the orders from the Triumvirate and go on to win decisive battles at Tucumán and Salto. However despite these victories his deeper penetration into upper Peru would result in defeat.
The First Triumvirate however was facing internal conflicts as the First Triumvirate was rather conservative in nature. The removal of prominent liberals from power would alienate the liberal faction that felt empowered thanks to the May Revolution. Thus the generals José de San Martín and Carlos María de Alvear would work with the dissident liberals to depose the First Triumvirate and set up the Second Triumvirate. Juan José Paso, Nicolás Rodríguez Peña, Antonio Álvarez Jonte would be elected to lead this Triumvirate.
The events of the second Triumvirate coincided with the revolution of October 8, 1812 which when they called for the National Assembly in 1813 called the Assembly of the Year XIII was the next big step on the path towards independence from Spain. Though by the end of the Assembly independence was not declared it did replace the Second Triumvirate with the first government of Argentina known as the United Provinces of Rio de la Plata. The United Provinces would be lead by a supreme director and a council of state.
With the unsuccessful Third Upper Peru campaign and more importantly the restoration of king Ferdinand to the throne of Spain, the question of independence had to be settled once and for all. Thus the Congress of Tucumán was called and one year after the creation of the United Provinces would Independence be declared. However, they excluded representatives from Sante Fe, Entre Ríos, Corrientes and the Banda Oriental whom formed a rival Federal League sometimes called the League of Free People. This would set the stage for future conflicts within the United Provinces.