On August 21, 1808, an act of fealty was sworn to Ferdinand VII.  This, nevertheless, met with disapproval on the part of many Argentines, who desired the establishment of a junta similar to that of Seville.  The party in favour of this increased rapidly in strength, and shortly afterwards the Viceroy, Liniers, resigned.  Although he had to a certain extent the support of the patriot party, his position in the face of the complicated situation had become extremely difficult.  He was succeeded on July 30, 1809, by Baltasar Hidalgo de Cisneros.  The latter lost no time in giving proof of liberal intentions.  He opened the ports to English vessels, and the commercial situation of the country, which had been deplorable, improved immediately.

In the meanwhile some revolutionary outbreaks at Chuquisaca and La Paz were suppressed by the Royalist troops with a brutality and wanton slaughtering which roused a storm of indignation in Buenos Aires.  Cornelio de Saavedra, one of the patriot leaders in the capital, succeeded, however, in preventing an open rising, since this would undoubtedly have been premature.

A secret society was now formed in Buenos Aires, counting in its ranks Belgrano, Nicolas Rodriguez Pena, Manuel Alberdi, Viamonte, Guido, and others.  From this nucleus the regiment of patricios was formed, and was commanded by Cornelio de Saavedra.  The chief object of this society was the foundation of an adequate representative Government.  To this end its members worked towards the abolition of the Viceroyalty and the formation of a new species of Constitution.  On May 22, 1810, a great meeting was held at which it was resolved that the authority of the Viceroyalty had expired.  On this it was proposed that a junta should be created.  Confusion, dispute, and intrigue followed; but the mind of the people was made up, and its will was no longer to be denied.

The Viceroy, de Cisneros, reluctant to oppose the now strongly expressed popular will, on May 25, 1810, resigned his office in the presence of an immense multitude.  From this day the independence of Argentina is officially counted, for on the spot a junta was established.  Its members were Saavedra, Belgrano, Alberdi, Castelli, Azcuenaga, Matheu, Larrea, Paso, and Moreno.

While all this was occurring in Buenos Aires, strong Royalist sympathies continued to prevail in the provinces.  Montevideo, too, showed itself hostile to the new Government.  From this base the Royalists were able to strike at the new republican head-quarters at Buenos Aires, and on February 18 a Spanish fleet sailed to the spot and blockaded the capital.  The patriots now made their first important move.  A force of 1,200 volunteers, commanded by Ocampo and Balcarce, marched against Cordoba, where Liniers and Concha were in command of the Royalist forces.  These latter were defeated and their leaders executed.  Flushed by its success, the Argentine army then invaded Peru.  A little later followed the victory of Suipacha, after which all the country in the neighbourhood declared itself openly for the revolutionists.