The Aragonese-Arborea army could count on thousand men and several siege engines, while the Pisan town of Villa di Chiesa provided for his defence of 250 knights, 1,000 troops, which included 128 crossbowmen, and 600 "townspeople", as well as of massive defensive walls.

The Aragonese also suffered numerous defections;[1] many in fact, given the unexpected long duration of the war, returned to the Iberian lands well before the end of the military operations.

For months the crossbowmen of Villa di Chiesa inflicted heavy losses on the Aragonese army that could not penetrate inside the walls.

At the entrance of the Iberian troops in the city everything edible had been consumed, according to reports, the besieged ate even mice, cats, dogs, and birds before capitulating.

The Aragonese continued with their march to Castel di Castro, defeating another Pisan army at the battle of Lucocisterna, on the 29 February.