The Spanish–Portuguese War between 1762 and 1763 was fought as part of the Seven Years' War. Because no major battles were fought, even though there were numerous movements of troops and heavy losses among the invaders—decisively defeated in the end—the war is known in the Portuguese historiography as the Fantastic War.
Background
When the Seven Years' War between France and Great Britain started in 1756, Spain and Portugal remained neutral. Their differences in South America had been settled by the Treaty of Madrid. King Ferdinand VI of Spain's prime ministerRicardo Wall opposed the French party who wanted to enter the war on the side of France. Everything changed when Ferdinand VI died in 1759 and was succeeded by his younger half-brother Charles III of Spain. Charles was more ambitious than his brother, and sought to preserve Spain's prestige as a European and colonial power. By 1761 France looked like losing the war against Great Britain. Furthermore, Spain suffered from attacks by English privateers in Spanish waters and claimed compensation. Fearing that a British victory over France in the Seven Years' War would upset the balance of colonial power, Charles signed the Family Compact with France in August 1761. This brought war with Great Britain in January 1762. After Portugal had been struck by the disastrous 1755 Lisbon earthquake, Prime Minister Sebastião José de Carvalho e Melo, Marquis of Pombal directed all efforts towards the reconstruction of the country and neglected the armed forces, for which he had little interest anyhow. By the Treaty of El Pardo between Spain and Portugal, all aspects of the Treaty of Madrid were null and void.
War
Spain agreed with France to attack Portugal which remained neutral, but which was an important economic ally of Great Britain. France hoped that this new front would draw away British forces, now directed against France. The triple Franco-Spanish invasion of Portugal in Europe, on 5 May 1762, was followed by a Spanish invasion of Portuguese territories in South America. While the first ended in humiliating defeat, the second represented a stalemate: Portuguese victory in Northern and Western Brazil; Spanish victory in Southern Brazil and Uruguay.
Peninsular action (main theater)
During the war, a Franco Spanish army of about 42,000 men, first led by the Marquis of Sarria and then by the Count of Aranda, invaded Portugal in 1762, at three different regions in three different times: provinces of Trás-os-Montes, province of Beira and Alentejo. They were faced by ferocious popular resistance and, from the middle of the second invasion onwards, by a tiny Anglo-Portuguese army of nearly 15,000 men superiorly commanded by the Count La Lippe. In the first invasion, the Spaniards – whose final goal was Oporto, the second city of the Kingdom – occupied without any opposition several undefended towns and ruined fortresses of the Province of Trás-os-Montes. The guerrillas exploited the mountainous nature of the province to cut off the Bourbon's supply and communication lines with Spain as well as to inflict heavy losses on the invaders. The populations abandoned their villages inducing famine among the Spaniards, who launched two offensives towards Oporto: the first was defeated by the militia and peasants at the battle of Douro and the second was beaten off at the Mountains of Montalegre. This failure and the arriving of Portuguese reinforcements forced the now diminished Spanish army to retreat into Spain, abandoning all their conquests. After this defeat, the Franco-Spanish commander, Sarria, was replaced by the Count of Aranda. During this first invasion of Portugal, the total Spanish casualties, according to a contemporaneous French source, general Dumouriez, were 10,000 men: prisoners, deserters or deaths by hunger, guerrilla's ambushes and disease. At the request of Portugal, one British force of 7,107 soldiers and officers landed in Lisbon, deeply reorganizing the Portuguese army. The supreme command of the allied army was delivered to one of the best soldiers of his time: the Count of Lippe. In the beginning of the second invasion, the Franco-Spaniards were successful and took several poorly equipped Portuguese fortresses and towns, including Almeida. However, the Anglo-Portuguese army defeated a Spanish corps who was preparing another invasion through the province of Alentejo and avoided the Spanish attempt of crossing the river Tagus, defeating them at Vila Velha. The allied army eventually stopped the Bourbon army's march toward Lisbon in the mountains near Abrantes and used a scorched earth strategy – in cooperation with the rural population – to starve the invaders: peasants abandoned their villages, destroying or taking with them all the food, while the guerrillas attacked their logistic lines. The invaders had to choose between stay and starve or withdraw. The outcome was the destruction of the Franco-Spanish army, whose remnants – leaving their wounded and sick behind – were chased to Spain by the Anglo-Portuguese army and peasants, after two encirclement movements delineated by a Portuguese force under general Townshend toward the enemy's rear: the first move forced the Bourbons to withdraw from the hills east of Abrantes to Castelo Branco, while the second made them flee to Spain. The Spanish headquarters, was captured by the Allied army who thus made thousands of prisoners. The total Franco-Spanish losses in this second invasion were evaluated by a contemporaneous Bourbon source as 15,000 men, while the total casualties for both the invasions were about 30, 000 men, according to the British ambassador in Portugal, Eduard Hay. As explained by Historians Danley Mark and Patrick Speelman: During the third Spanish offensive, the Spaniards attack by surprise two Portuguese towns – but were defeated - and had to retreat again before the reinforced and advancing Anglo-Portuguese army who took some prisoners. Additional Spanish prisoners were taken when a Portuguese force led by British Colonel Wrey entered Spain and attacked the region of Codicera. Thus, Aranda, with his forces ruined and demoralized, sent to Lippe an emissary proposing an armistice, which was accepted and signed on 1 December 1762.
Cevallos advanced and won a still greater victory when he conquered most of the vast and rich territory of the so-called "S.Peter´s Continent" – the present day Brazilian state of Rio Grande do Sul where the Portuguese had only up to 1,000 men. São José do Norte and the capital – S. Pedro do Sul- were abandoned without a fight. However, the Spaniards were routed by the Portuguese in the battle of Santa Bárbara, when an invading army of 500 Spaniards and 2,000 Indians, in cooperation with Cevallos, tried to conquer Rio Pardo, nearly the only remaining Portuguese territory in Rio Grande do Sul: seven cannons, 9,000 heads of cattle and 5,000 horses were captured. This huge territory would be completely retaken by the Portuguese during the so-called "deaf war".
Mato Grosso
A Spanish army of 600 or 1200 men tried to retake the territory of Mato Grosso, in the right bank of the Guaporé River, besieging the fortress of Conceição. The 100 defenders, after receiving reinforcements, not only resisted but conquered and occupied – until the end of the war – the reductions of S. Miguel and S. Martin, which were main sources of Spanish supply and were located on the Spanish side of the river Guaporé. They also used biological warfare. The Spaniards withdrew – after losing half of their men from hunger, disease and desertion – leaving the Portuguese in the possession of the disputed territory. Rolim Moura was rewarded with the vice-royalty of Brazil for this victory.
Rio Negro
The Portuguese conquered most of the valley of Rio Negro, expelling the Spaniards from :pt:Forte de São Gabriel da Cachoeira|S. Gabriel and :pt:Forte de São José de Marabitanas|S. josé de Maribatanas and building two fortresses there with the Spanish cannons.
Aftermath
At the Treaty of Paris, the prewar situation between Spain and Portugal was restored:
Spain was forced to return to Portugal the small cities of Almeida and Chaves on the Hispano-Portuguese frontier. All the other cities and strongholds had been retaken by the Anglo-Portuguese army during the chase of the remnants of the Franco-Spanish troops.
The Spanish-Portuguese colonial conflict during the Seven Years' War ended in a tactical stalemate, but it would represent a Portuguese strategic victory in the short run. Apart for the forts of Santa Teresa and San Miguel, the Spaniards would lose to the Portuguese all the territory conquered during the war. Colonia do Sacramento was given back by the same treaty and Rio Grande do Sul would be retaken from the Spanish army during the undeclared war of 1763–1777 and Portugal retained all its conquests.
