First Cevallos expedition

The First Cevallos expedition was a military action between September 1762 and April 1763 by the Spanish led by Pedro Antonio de Cevallos against the Portuguese in South America, as part of the Seven Years' War.

Prelude

In January 1762 Spain joined France against Great Britain in the Seven Years' War, in accordance with the third Pacte de Famille. The plan was to attack Portugal, which had been neutral up to then, but which was an important economical ally of Great Britain.
On May 9 Spain invaded Portugal, and also decided to attack Portugal in South America, and in particular to take the long disputed Colonia del Sacramento.

The expedition in 1762

In the first days of January 1762 the frigate "Victoria" commanded by Carlos José de Sarriá, sailed from Cadiz to Buenos Aires with orders for the Governor of Buenos Aires, Pedro Antonio de Cevallos, to attack and take Sacramento.

He started preparations and in September 1762 he had assembled enough men and ships to launch an attack. The fleet sailed across the Rio de la Plata, and disembarked on September 14. The army was joined by a force of 1200 Indians on October 1. The siege of the city started on October 5.

The relations between Cevallos, who commanded the army, and Sarria, who commanded the fleet, were very bad. After disembarking the army and without approval of Cevallos, Sarria sailed his fleet of 16 ships back to Buenos Aires.

Luckily for the Spanish, the Portuguese were ill prepared and on October 31 1762 Silva Fonseca, the governor of the city, capitulated.

The sinking of the Lord Clive

Great Britain, which was now officially at war with Spain, did not participate in this battles, but the East India Company had plans to conquer Spanish territory in South America and bought two old warships from the Admiralty. The biggest ship was HMS Kingston (1697) which was renamed "Lord Clive" (60), the other ship was the "Ambuscade" (40).

The small squadron, under the command of Robert McNamara left Lisbon on August 30 and was joined in Rio de Janeiro by two Portuguese warships (among which was the frigate "Glória" (38)) transporting 500 foot soldiers, and five storeships. On November 2, the squadron sailed from Rio de Janeiro towards the mouth of the Río de la Plata to attack Buenos Aires and Montevideo, but soon abandoned the project because of the strong resistance of the Spaniards.

On January 6 1763, the squadron decided to attack and retake Colonia de Sacramento. The Spanish squadron under Sarria, fled at the first sight of the enemy. Sarria even had his flagship destroyed to prevent it falling into enemy hands, after the battle was already over. He was trialed for cowardness but acquitted.
Abandoned by their fleet, the Spanish coastal defences fought well. The "Lord Clive" came under their fire, caught fire and sank. There were 272 fatalities on board, including the expedition's commander Captain Robert McNamara. The rest of the allied fleet returned to Rio de Janeiro.

The expedition in 1763

Still in control of Sacramento, Cevallos marched his army in the spring of 1763 to the east and took on April 19 the "Santa Teresa fortress", near the present-day city of Chuy on the Uruguay-Brazilian border, and "Santa Tecla" and "San Miguel" a few days later. On April 24 he arrived at Río Grande de San Pedro only to learn that the peace had been signed and that the war was over.

Aftermath

Sacramento and all the territory conquered by the first Cevallos expedition were given back to Portugal in the Treaty of Paris (1763). This was part of a deal to regain Cuba for the Spanish crown, which had been lost in the British expedition against Cuba and which was of much greater importance than these far-away territories.

Source

* [http://www.todoababor.es/articulos/esp-port.htm Guerras entre España y Portugal en la cuenca del Río de la Plata (in Spanish)]