[1] He saw his first service (as a cadet) in the defense of Ceuta against the Moors in 1784, distinguishing himself in outings that destroyed the batteries of the besieger, forcing him to lift the siege.

[1] The Treaty of San Ildefonso, allying Spain and France against England, brought him to fight alongside the French and under the orders of Admiral José de Mazarredo[1] (1797)[citation needed], with the ship Bahamas from 1799 to 1802.

He followed the actions of Castaños encased in his artillery and was present at the battle of Tudela (23 November 1808), a Spanish defeat that forced the army to retreat to Zaragoza.

[1] In 1814 Ferdinand VII created the Order of Saint Hermelegild (Orden de San Hermenegildo) to recognize his supporters during his years of captivity and La Serna was awarded this distinction.

Thus their relation started on the wrong foot, impairing La Serna's command of the Army of Upper Peru: his orders included that of reorganizing those troops and creating a General Staff, and Pezuela was against both measures.

[1] The 21-day crossing of the mountains from Argentina was arduous,[citation needed] but the Battle of Chacabuco was a resounding success for San Martín who defeated the troops sent to stop him — greatly helped in that by the contradictory orders and doubts of Royal Governor Field Marshal Marcó.

[1] Pezuela decided to recover Chile and ordered La Serna to form a reserve force to support the action he planned.

In December 1817 the expedition for the reconquest of Chile left under the command of General Osorio (Pezuela's son-in-law), and arrived at Talcahuano in February 1818.

Meanwhile, the formation of the reserve corps continued to widen the gap between La Serna and Pezuela, although it was eventually organized according to the viceroy's wishes.

[3] While waiting for this resignation's formal acceptance, in the spring of 1819 La Serna repeated with complete success the previous unfortunate expedition to Jujuy, giving a severe punishment to the gauchos who harassed his army and taking thousands of cattle.

The Riego coup d'état [es] on 1 January 1820, however, not only changed the political regime in Spain, but also meant the abandonment of the great expedition of 18,000 men which could have restored the King's authority in South America.

The Royal Order asked the insurgents to swear by the newly implemented Cádiz Constitution of 1812; if they did not accept that, commissioners were to be sent to Madrid and in the meantime hostilities should be suspended.

[1] La Serna thought that the insurgents would not be willing to swear allegiance to the constitution; so he proposed that cash be offered, as well as the control of Tacna and Arica.

The city had endured a year-long blockade but became isolated by sea after November 1820 when Cochrane attacked and took the frigate Esmeralda; and it was also surrounded by land with guerrilla forces that had come from the Andes.

La Serna, again, clashed with Pezuela and saw Lima as expendable – for practical reasons: it was undefendable without a functioning navy, and it was very difficult to provision.

[5] All the members of the military Ejército Real [es] signed a declaration accusing the viceroy of inaction, of having made many tactical mistakes and of failing to defend the city against San Martín.

Viceroys being deposed were no novelty: it had already happened in Mexico, Río de la Plata and New Granada – but only in the context of forming juntas.

[6] He gave up 60 per cent of his salary to alleviate the economic situation of the viceroyalty; following this, all the army chiefs and ministers of the Audiencia agreed to retain half their assets and to reintegrate them when conditions were favourable.

[1] The instructions that Manuel Abreu brought were quite similar to those given to Pezuela: essentially that hostilities should be suspended; and that the Constitution should be sworn in and deputies from the independantists sent to the Spanish Parliament.

[4] La Serna took the strategic measure that he had already proposed six months earlier: he evacuated Lima, without resources because of the blockade of the Chilean fleet, and withdrew inland.

[1] When La Serna was in position to assist Callao – besieged by land since 12 July 1821 –, he sent Canterac[1] on August 24 with 4,000 men[citation needed] – less than that of San Martín, who however did not dare to interpose himself.

When this expedition returned to the mountains, La Mar[h] surrendered the fortresses[1]on September 19, 1821[citation needed], due to lack of supplies.

Olañeta seemed to accept peace,[12] but as soon as Valdés left, he went back to criticizing La Serna and published another declaration in that sense in June.

[17] He rose up in arms claiming that Ferdinand VII had regained his whole power; that this news had come through Buenos Aires and he, by his proximity at the border with that country, was the first to receive it.

The battle of Lava (in the present Linares Province, Potosí Department ; 17 August 1824[18]) resolved the conflict but left Valdés' army very diminished: he had to withdraw garrisons from the cities to rebuild it in part and, after a march of one thousand eight hundred kilometers, meet with the viceroy.

There, he learnt that the king had congratulated him for his dedication, that he had been officially appointed viceroy of Peru, and that he had been awarded the Cross of San Fernando, as well as the title of Count of the Andes.