The battle proved decisive not of the fortunes of Chile alone but of those of all Spanish South America.

As a viceroy of Peru later confessed, "it marked the moment when the cause of Spain in the Indies began to recede." Named supreme director by the people of Santiago, O'Higgins fought vigorously though ineffectually to drive out the royalists who, reinforced from Peru, held the region south of the capital.

That he failed did not deter him from having a vote taken under military auspices, on the strength of which, on February 12, 1818, he declared Chile an independent nation, the date of the proclamation being changed to the 1st of January, so as to make the inauguration of the new era coincident with the entry of the new year.

San Martin, meanwhile, had been collecting reinforcements with which to strike the final blow.

On the 5th of April, the Battle of Maipo gave him the victory he desired.
Except for a few isolated points to the southward, the power of Spain had fallen.
Until the fall of Napoleon in 1815 it had been the native loyalists who had supported the cause of the mother country in the Spanish dominions.
Henceforth, free from the menace of the European dictator, Spain could look to her affairs in America, and during the next three years dispatched twenty-five thousand men to bring the colonies to obedience.
These soldiers began their task in the northern part of South America, and there they ended it--in failure.