The United Restoration Army, led by Chilean General Manuel Bulnes, consisting mainly of Chileans and 600 North Peruvian dissidents, attacked the Peru-Bolivian Confederation forces led by Andrés de Santa Cruz in northern Peru, 200 kilometers (120 mi) north of Lima.

By this pact, Chile agreed to resume commercial trade and the Confederation would recognize and pay the Chilean efforts in the Peruvian independence war.

[3] Despite the victory, Bulnes left the city by November, and marched to Huacho in the North Peruvian territory, forced by local animosity, lack of supplies and diseases.

Bulnes continued marching north and Santa Cruz resumed the persecution seeking to deliver a final blow to cement Confederation's dominance in the region.

Its commanding officer, General Andrés de Santa Cruz; was regarded as a resourceful tactician and a capable leader.

Both forces were separated by a short valley formed by the Santa River and the mountains, with the Punyán, Ancash and Pan de Azúcar hills at the far end of this site.

[4] The Valparaíso Battalion Sergeant Jose Alegría raised the Chilean flag on the Pan de Azúcar Hill summit.

Bulnes ordered the Portales Battalion to aid Urriola, a maneuver that obliged the Bolivians to pull out of the valley and withdraw to Herrera's positions with the loss our a third of its initial strength.

With the Pan de Azúcar and Punyán hills conquered, Bulnes then planned a frontal attack on Santa Cruz army, which was arranged in a line of trenches on the opposite bank of the Ancash River.

So, with the Chilean forces converging on the river bank, the Colchagua and Valdivia battalions were dispatched to engage the Confederate right flank, guarded by Herrera's division, while the Portales, Cazadores de Perú and the Huaylas battalions were ordered to attack Col. Moran's division.

The five cannon battery of Col. Marcos Maturana set up on the Punyán heights began to shell and slowly dismantle the Confederate trenches.

Once Bulnes' troops crossed the river, then the battle covered the entire front line, with the Restorer soldiers out in the open and the Confederates firing at them from their trenches.

Soon after, the cavalry was sent in to cut off the Chilean retreat while the infantry advance from their protected positions to attack the Restorers troops in the open field.

However, the Chilean cavalry attacked again with full force, obliging Perez de Urdinea to regroup with the Confederate infantry trying to retreat to their trenches.

In a massive third charge, Baquedano broke Santa Cruz's left flank and the entire Confederate front collapsed.

Santa Cruz, followed by his generals Riva Agüero, Cerdeña and Miller, left the battlefield around 15:00 hrs.

Santa Cruz had around 3,000 dead, including two generals, 9 colonels, 100 officers and 2,500 soldiers, around half of its effective force.

Santa Cruz was exiled, first to Guayaquil, Ecuador, then to Chile and finally to Europe,[6] where he died in Beauvoir, France, on 25 September 1865.