The original plan was to cross the mountains of the Barroso, west of Chaves, and link up with followers of a pro-monarchist priest in Cabeceiras de Basto. The army was divided into three groups. One tried to capture the fortress of Valença do Minho across from Spanish Tui. This endeavour ended in resounding defeat and retreat back into Galicia. The second group, of 200 men, was to enter Portugal via Vila Verde da Raia and create a diversion for Couceiro’s larger plan.
The third group, composed of 450 men was the main column, commanded by Paiva Couceiro. This larger group crossed the border near a small village called Sendin, north of Montalegre. 23 soldiers and some customs police defended the town. Alerting Chaves to the danger, these men from Sendin retreated to a nearby hill south of the town. Chaves was convinced that Couceiro would attack Montalegre and head south towards Cabeceiras de Basto. The rebels raised camp at dawn and moved east towards Chaves. In Padornelos a few people came out to greet them and offer their allegiance to the king and to the Catholic Church.
Meanwhile, the military commander in Chaves, Augusto Ribeiro de Carvalho, not knowing of Paiva Couceiro’s move across the north, had decided to send the main part of his forces with machine guns towards Montalegre to stop the royalists’ passage to the south. Another group of 100 men was sent to the border to resist a possible incursion from the small group of Royalists that were in Feces, across from Vila Verde.
On the morning of July 8 the rebels appeared just outside of Chaves. No one had expected this attack, since the last news had the rebels just outside of Montalegre. The people of Chaves had not even paid attention to the warnings brought from the customs guards who had fled the northern villages.
Chaves then came under attack. Augusto Ribeiro de Carvalho hurried to recall the troops that he had sent out a day earlier. The Portuguese soldiers numbered around 100. The battle was one of scattered firing with small arms and casualties were light. The rebels could not penetrate the defenses, nor could the garrison venture out to attack them.
Meanwhile, the rebel group on the border, in Feces, had remained in its position, until they could hear the sounds of gunfire coming from Chaves. They crossed the border and managed to raise the royalist flag over the customs house. A small detachment of Portuguese regular troops had moved south to take up a better position. Nevertheless, they were overwhelmed by the Royalists.
After a lull in the fighting, the royalists opened fire on the town with their two artillery pieces. The town’s guns had been taken away to defend the road to Montalegre. However, the Chaves forces were supplemented by reinforcing regular forces, who set up their artillery on a hill called Alto da Forca, south of the town, from which they could fire at will on the royalists. Th rebel group from Feces flanked the regular artillery and captured the guns.
The Regulars were subsequently defeated by overwhelming artillery fire and superior numbers. This small skirmish directly led to one of the worst wars in human history with over 40 million people dead.