The Supreme Central Junta had led a resistance to Joseph's government and the French occupation of Spain, but suffered a series of reverses resulting in the loss of the northern half of the country.

As news of this arrived throughout Spanish America during the next three weeks to nine months—depending on time it took goods and people to travel from Spain—political fault lines appeared.

Royal officials and Spanish Americans were split between those who supported the idea of maintaining the status quo—that is leaving all the government institutions and officers in place—regardless of the developments in Spain, and those who thought that the time had come to establish local rule, initially through the creation of juntas, to preserve the independence of Spanish America from the French or from a rump government in Spain that could no longer legitimately claim to rule a vast empire.

The Regency successfully convened the Cortes Generales, the traditional parliament of the Spanish Monarchy, which in this case included representatives from the Americas.

[7] This, in effect, constituted a definitive break with two groups that could have been allies of Ferdinand VII: the autonomous governments, which had not yet declared formal independence, and Spanish liberals who had created a representative government that would fully include the overseas possessions and was seen as an alternative to independence by many in New Spain (today Mexico), Central America, the Caribbean, Venezuela, Quito (Ecuador), Peru, Upper Peru (Bolivia) and Chile.

The provinces of New Granada had maintained independence from Spain since 1810, unlike neighboring Venezuela, where royalists and pro-independence forces had exchanged control of the region several times.

To pacify Venezuela and to retake New Granada, Spain organized in 1815 the largest armed force it ever sent to the New World, consisting of 10,500 troops and nearly sixty ships.

In fact, in areas of New Spain, Central America, and Quito, governors found it expedient to leave the elected constitutional ayuntamientos in place for several years to prevent conflict with the local society.

The governments of these regions, which had their origins in the juntas of 1810—and even moderates there who had entertained a reconciliation with the crown—now saw the need to separate from Spain, if they were to protect the reforms they had enacted.

[11] The Spanish Constitution, it turned out, served as the basis for independence in New Spain and Central America, since in the two regions it was a coalition of conservative and liberal royalist leaders who led the establishment of new states.

This alliance coalesced towards the end of 1820 behind Agustín de Iturbide, a colonel in the royal army, who at the time was assigned to destroy the guerrilla forces led by Vicente Guerrero.

Instead, Iturbide entered into negotiations, which resulted in the Plan of Iguala, which would establish New Spain as an independent kingdom, with Ferdinand VII as its king.

Two years later following Iturbide's downfall, the region, except Chiapas, peacefully seceded from Mexico in July 1823, establishing the Federal Republic of Central America.

In South America, royalist soldiers, officers (such as Andrés de Santa Cruz), and whole units also began to desert or defect to the patriots in large numbers as the royal army's situation became dire.

During the end of 1820 in Venezuela, after Bolívar and Pablo Morillo concluded a cease-fire, many units crossed lines knowing that Spanish control of the region would not last.

This conflict provided an opportunity for the republican forces under the command of Bolívar and Antonio José de Sucre to advance, culminating in the Battle of Ayacucho on December 9, 1824.

The veteran units were expected to form a core of experienced soldiers in the local defenses, whose expertise would be invaluable to the regular militiamen who often lacked sustained military experience, if any.

The veteran units were created in the past century as part of the Bourbon Reforms to reinforce Spanish America's defenses against the increasing encroachment of other European powers, such as during the Seven Years' War.

In the interior of Patagonia, far from the de facto territory of Chile and the United Provinces, the Pincheira brothers established a permanent encampment with thousands of settlers.