On returning to Spain, by the end of two months he had recruited 1,500 troops and he was appointed Colonel-in-chief of the 2nd Platoon of the Catalonia Light Infantry, based at Montserrat.

[1] Appointed General-in-chief of the Ampurdán, he directed the action at La Junquera (19 October) where, despite being wounded by a bayonet, he went on to kill the seven enemy combatants that had surrounded him.

On 16 April, in the mountains of Puigventós, accompanied by the Alcántara Cavalry Regiment, they defeated an entire battalion, excepting five officers and 30 soldiers that were taken prisoners.

Shortly thereafter, he devised a plan to recover the fortress at San Fernando de Figueras: he was able to distract the French division based in the Ampurdán by taking the fortresses of Castellfullit and Olot, taking over five hundred prisoners and then, on 16 June, penetrated the enemy lines at bayonet point and managed to enter the castle with a large convoy.

[1] He stayed at the castle throughout the siege, participating in several sorties, including on 3 May, when his troops penetrated the French line and attacked the town of Figueras, holding the square for several hours after the Spanish Army had been defeated and had retreated.

On a sortie on 7 May, he was able to capture a French convoy on its way from Figueras to La Junquera and finally, in the night of 16 May, his three hundred infantrymen were able to safeguard the departure of the garrison's cavalry by breaching the enemy lines four times at bayonet point, without the loss of a single Spanish soldier but capturing around twenty French soldiers.

When Tarragona finally fell to the French, Eroles's troops supported the embarkation of the Valencia división and repulsed Suchet's vanguard at Mataró and Arenis de Mar.

[1] He followed that achievement with a rapid march to Cerdaña, where he surprised General Gavean,[1] forcing him to abandon Puigcerdá, and on 24 October was able to push him back to the vicinity of Mont-Louis, in the Pyrénées-Orientales of France.

[1] On 5 December 1811 he faced General Decaen at Sant Celoni, who was unable to move him from his positions; and again at La Garriga two days later, preventing the French forces from taking Vich.

British Commodore Edward Codrington, then commanding a Royal Navy squadron in the Mediterranean Sea charged with harrying French shipping, was present at the combat, having come on shore to confer with Eroles, with whom he often collaborated,[4] regarding an action against Tarragona.

[1] At Tarragona, Eroles prevented the French garrison from leaving the city (11 December); that same day, he carried out a successful attack on the castle at Coll de Balaguer, capturing it.

[1] Shortly thereafter, he received a letter from the King ordering him to arrest Copons on criminal charges, which he did on the night of the 4–5 June 1814 and had him confined at Sigüenza.

[1] A notorious conspirator, together with Bernardo Mozo de Rosales, marquis of Mataflorida[1] and the Archbishop of Tarragona, Jaime Creus Martí, Eroles was a member of the Urgel Regency,[2] an interim government established by the Spanish absolutists in August 1822 (during the Triennium) based in Seo de Urgel, a fortress held by the Royalist forces some weeks earlier.

The Junta Provisional de Gobierno, presided by Francisco de Eguía, appointed Eroles Captain General of Catalonia in April 1823, post confirmed by the King the following October,[1] around the time Ferdinand VII broke his oath and again repealed the Constitution of Cádiz, declaring null and void the acts and measures of the liberal government.

[1] Following the fall of the Triennium, Eroles was appointed Captain General of the Royal Armies on 28 December 1824, but died less than a year afterwards, suffering from dementia.

[1] After having wiped out an entire battalion in the mountains of Puigventós (16 April 1811) Eroles came to be known by the enemy as the "Nero of Catalonia" (Diario de Barcelona, 9 August 1811).

)[7]Benito Pérez Galdós refers to Eroles on several occasions in his 1877 novel Los Cien Mil Hijos de San Luis (Hundred Thousand Sons of Saint Louis), part of his Episodios Nacionales.

The following is an example: These were the Baron de Eroles and don Jaime Creux, Archbishop of Tarragona, both of them, just like Mataflorida, from the humblest of classes, brought out of obscurity by these revolutionary times, which wasn't really a very strong argument in favour of absolutism.

This fact, which had been observed since the previous century, was expressed by Louis XV, when he said that the nobility needed to be covered in manure in order to be made fertile.Of these three regents, the most likeable was Mataflorida, who was also the most learned; the most tolerant was Eroles, and the most evil and unpleasant, Don Jaime Creux.