The revolutionary José Gervasio Artigas had returned…
May 1811 CE
On April 11, he had issued the Mercedes Proclamation, assuming control of the revolution.
The Governor of Montevideo and new Viceroy of Río de la Plata, Francisco Javier de Elío, has appointed frigate-captain José Posadas at the head of the forces loyal to Spain.
Posadas has installed his headquarters at San Isidro Labrador de Las Piedras near Montevideo, to provoke a decisive battle against the revolutionaries.
José Artigas has meanwhile camped near Nuestra Señora de Guadalupe with an army of a thousand men.
The army of Posadas counts twelve hundred and thirty men, of which some two hundred will defect to Artigas in the middle of battle.
The battle is fought on May 18 at Las Piedras and results in a total victory for the revolutionaries.
José Posadas capitulates.
It was at this occasion that Artigas pronounces his famous sentence "Curad a los heridos, clemencia para los vencidos" (Cure the injured, mercy to the vanquished), an unusual decision in these times, referring to the Spanish wounded and prisoners.
One of the casualties on the revolutionary side is Manuel Artigas, nephew of José Artigas.
Both armies fight in the name of King Ferdinand VII of Spain.