Trouillas nestles in a plain on the Canterrane stream at an altitude of about 100 meters. Mas Deu, an establishment founded by the Knights Templar in medieval times, is located 2.4 km to the east. Thuir lies five km to the northwest. Ricardos defended these positions with a force of 17,000 soldiers and 38 cannons. The second battalion of the BarcelonaInfantry Regiment arrived, but this reinforcement did not make up for the heavy Spanish losses suffered at Peyrestortes. Dagobert attacked the Spanish defenses with 22,000 soldiers. The French order of battle included the 7th, 61st, 70th, and 79th Infantry Demi-Brigades, as well as the National Guards of Gers and Gard. Dagobert preferred to envelop the Spanish position from the west, but Fabre and the other generals persuaded him to make a frontal attack. So he sent General of Brigade Louis Antoine Goguet's division to assault the Spanish left flank at Thuir while sending a flanking column to attack that town from the west. D'Aoust's division was ordered to attack the Spanish right flank at Mas Deu, while Dagobert led his own division in an attempt to pierce the Spanish center. Believing that Thuir was the focus of the main French effort, Ricardos posted General Crespo and only 3,000 men to defend the Spanish right. He shifted the troops of LG Pedro Téllez-Girón, 9th Duke of Osuna and LG Luis Firmín de Carvajal, Conde de la Unión to hold Thuir. Dagobert's attack pushed back the Spanish center and forced its way into the main camp at Trouillas. Meanwhile, Goguet ran into a concentration of Spanish infantry and artillery on the west flank at Thuir and was beaten. Ricardos personally led a cavalry charge to break up the flanking column, then he returned to the crisis of the battle in the center. D'Aoust merely skirmished with Crespo near Mas Deu and never mounted a serious threat to the Spanish right. This allowed Ricardos to mass his cavalry against Dagobert's division. After disposing of Goguet, de la Unión marched to Trouillas to take the French center in reverse. Three French demi-brigades were surrounded and many prisoners taken. After an all-day battle Dagobert retreated northeast to Canohès. The Spanish victory was also helped by disorganization and poor logistical arrangements on the part of the French.
Result
Though Dagobert admitted only 1,500 casualties, historian Digby Smith notes that the French actually suffered 3,000 killed and wounded, with 1,500 soldiers and 10 artillery pieces captured. The Spanish army lost a total of 2,000 killed, wounded, and missing. De Courten and General Diego Godoy also fought for the Spanish. Representatives Fabre and Raymond Gaston removed the unsuccessful Dagobert from command of the army on 28 September and temporarily replaced him with d'Aoust. Dagobert returned to the Cerdagne with his division and sacked the Spanish town of Camprodon on 4 October. Though Ricardos gained the victory at Trouillas, he soon found it expedient to withdraw to the Tech River. On 3 October, the Spanish commander and 15,000 troops repulsed d'Aoust and 16,000 Frenchmen at Le Boulou on the Tech. In that action, 1,200 French soldiers became casualties against only 300 Spaniards.
