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 huge losses among the invaders—utterly defeated in the end—the war is known in the Portuguese historiography as the Fantastic War (Portuguese and Spanish: Guerra Fantástica).
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 (1750). King Ferdinand VI of Spain's prime minister Ricardo 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 melancholic brother. One of the main objects of Charles's policy was the survival of Spain as a colonial power and, therefore, as a power to be reckoned with in Europe.
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, he signed the Family Compact with France (both countries were ruled by branches of the Bourbon family) 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 (1761) between Spain and Portugal, all aspects of the Treaty of Madrid were null and void.
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 (main theater of the war, which absorbed the lion's share of the Spanish war effort), on 5 May 1762, was followed by a Spanish invasion of Portuguese territories in South America (a secondary theater of the war). 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 (first invasion of Portugal, May–June 1762), province of Beira (second invasion of Portugal, July–November 1762) and Alentejo (third invasion, November 1762). 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 (there were neither regular soldiers nor gunpowder in the entire province, except in the fortress of Miranda do Douro).
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 (including regular troops) forced the now diminished Spanish army to retreat into Spain, abandoning all their conquests (except Chaves). 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 (8,000 according to modern Spanish military historian José Luis Terrón Ponce).
At the request of Portugal, one British force of 7,107 soldiers and officers landed in Lisbon, deeply reorganizing the Portuguese army (7 to 8.000 regular soldiers). The supreme command of the allied army (from 14 to 15.000 men) was delivered to one of the best soldiers of his time: the Count of Lippe.
In the beginning of the second invasion (province of Lower Beira, July–November 1762), 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 (battle of Valencia de Alcántara) 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 (which by its position dominated the country) 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 (Castelo Branco), was captured by the Allied army who thus made thousands of prisoners (2 November 1762).
"The region was devastated, there were no provisions... The burning of villages punished the vengeance of the inhabitants; but these punishments only made crueler the fate of the Spanish armies.
Then the small Anglo-Portuguese army took the offensive. The Count of Lippe gave the order to attack. Loudon [in reality it was Townshend] was ordered to join the troops of General Lennox and to place himself between Almeida and Badajoz. This way, the line of retreat of the Aranda´s army... would be threatened. Aranda [immobilized by the excellent Anglo-Portuguese defensive positions in the mountains near Abrantes] was forced to choose between withdrawing or starve to death in Beira. (...). General Loudon [Townshend] managed to occupy Fundão, making the Spanish advanced guards withdraw. The Spanish army retreats [towards Castelo Branco, closer to the Spanish border], and the Portuguese troops advance, reoccupying Vila Velha, and the Loudon [Townshend]’s force recovers Penamacor and Monsanto; while another officer, Field Marshal Frazer, chased the enemy with two battalions and four cavalry regiments.
Then, taking advantage of the disorder caused by the withdrawal, The Count of Lippe outlined a plan that would imprison Aranda and all his army in Castelo Branco [The Spanish headquarters]. Bad weather delayed the operation and an informer reported the Spanish commander about the intentions of Lippe. The Spanish army hastily retreated to his own country. The last enemy troops withdrew ... and shortly after, the Portuguese occupied again the border posts with the exception of Chaves and Almeida ...",— In Arquivo Nacional.
The total Franco-Spanish losses in this second invasion were evaluated by a contemporaneous Bourbon source as 15,000 men (Dumouriez in 1766), while the total casualties for both the invasions were about 30, 000 men, according to the British ambassador in Portugal, Eduard Hay (8 November 1762).
As explained by Historians Danley Mark and Patrick Speelman:
"... Bourbon casualties mounted because the Portuguese peasantry waged a relentless war of revenge against deserters and retreating soldiers who they captured and massacred in large numbers (p. 452)....The Portuguese campaign, indeed the entire Spanish war, lay in ruins (p. 521)."— The Seven Year’s War: Global Views
During the third Spanish offensive (November, 1762), the Spaniards attack by surprise two Portuguese towns (Ouguela and Marvão) - 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 (19 November).
Thus, Aranda, with his forces ruined and demoralized, sent to Lippe an emissary proposing an armistice (24 November), which was accepted and signed on 1 December 1762.
South America (secondary theater)
In South America, the Spanish Cevallos expedition (3,900 men)  was more successful. In present-day Uruguay, they captured Colónia do Sacramento (with 767 defenders) and two other fortresses: fort of Santa Teresa (with 400 defenders), on 19 April 1763; and fort of San Miguel (with 30 defenders), in 23 April.
- Rio Grande do Sul (South of Brazil)
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 (soldiers and militia). 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 (1 January 1763), 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" (1763-1777).
- Mato Grosso (western Brazil)
A Spanish army of 600 or 1200 men (according to the sources) tried to retake the territory of Mato Grosso, in the right bank of the Guaporé River, besieging the fortress of Conceição (the "door" for the gold-rich Province of Mato Grosso). 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 (left bank). 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 (Amazonia, North Brazil)
In the Treaty of Paris the pre-war status quo 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 (Rio Negro Valley and Guaporé River’s right bank / Mato Grosso).
- "This disavowal is the consequence of the double humiliation that Spain has just undergone on the international scene, with the defeat of its army in Portugal and with the capture of Havana by the English. Confining itself to a disaster, the Seven Years' War marks a major shift in the Chalrles III policy …" In Glesener, Thomas- L´Empire des Exilés: Les Flamands et le Gouvernment de l´Espagne au XVIIIº Siècle., Casa de Velázquez, Madrid, 2017, p. 268.
- "When coupled with the defeats suffered in Portugal (...), the fall of Havana amounted to a loss of prestige from which Spain never recovered. " In Navy Records Society- Publications of the Navy Record Society, Vol. 114, George Allen & Unwin, Great Britain, 1970, p. xxxiv.
- "The war between Spain and Portugal ended favourably for the latter ... The Spaniards, notwithstanding their superior forces, had to retreat vanquished into their own country. The Count of Lippe soon returned as a conquering hero into his little German principality. " In Cobb, James Francis- Stories of Success, Jas. Tauscott and Son, London, 1872, p. 172.
- "Spain´s military weakness was revealed when its invasion of Portugal, Britain's ally, met with defeat." In Page, Anthony- Britain and the Seventy years War, 1744-1814 (Enlightenment, Revolution and Empire), 2014, P.28.
- "... and with regard to Portugal, the invasion of the neighbour kingdom by the Spanish troops was a military defeat. " In Pinedo, Emiliano Fernández de (Spanish); Novales, Alberto Gil (Spanish) and Dérozier, Albert (French)- Centralismo, Ilustración y agonía del antiguo regimen, 1715-1833, Editorial Labor, Spain, 1980, p. 219.
- "During Pombal's reign Portugal faced foreign threats, such as the Spanish invasion during the Seven Years' War in 1762. Even if Portugal was able to defeat the Spanish with the help of their British allies, this war of Spain and France against British hegemony made him concerned about Portuguese independence and Portugal's colonies. " In Leutzsch, Andreas; Vogt, Roland; Cristaudo, Wayne – European National Identities: elements, transitions, conflicts, Transaction Publishers, London, 2014, chapter 10, p. 188.
- "(…). Portugal had not accepted the invitation to join France and Spain in this alliance and the latter powers... invaded Portugal. England sent a fleet promptly to Lisbon with 8,000 soldiers who helped drive the invaders back and followed them into Spain herself. She had entered the war too late to help France or herself. The blows she had received were staggering (...)" In Hart, Francis Russel – The Siege of Havana: 1762, Houghton Mifflin, 1931, p. 52.
- "Portugal refused to enter the war against the English, and its territories were invades by French and Spanish troops (Trás-os-Montes, 1762). However, Portugal repelled the invaders, under the leadership of Wilhelm, count of Schaumburg-Lippe, and with aid from the English, as well as from Swiss mercenaries." In Delon, Michael- Encyclopedia of the Enlightenment, Routledge, New York, 2013, p. 1256.
- "The land on their own side [Portuguese side of the river Guaporé] afforded nothing on which they could rely, whereas the country of the [Spanish] Missions [left bank of the Guaporé] abounded with cattle... The Spaniards... designed... to intercept the communication [of the Portuguese in S. Rosa] with Para... and... Villa Bella. This blockade might be easily maintained, because they drew their supplies from the reductions; whereas the garrison [of S. Rosa], being confined to their own shore, would be distressed for food... and might thus be reduced without a blow. (...). The Portuguese...made an expedition against the Reduction of S. Miguel, which had been removed from the right Bank [to the left bank of the river Guaporé, in 1760, in accordance to the Treaty of Madrid, 1750]... they got possession of supplies which were intended for the [Spanish] army at Itanomas... the Portuguese kept possession of the territory of S. Miguel, which abounded with kine, horses and pigs... the Reduction of S. Martin voluntarily offered submission...D. António ventured to attack the Spaniards in their camp...the estacade was found too strong; but the boldness of this measure, thought unsuccessful, discouraged the Spaniards... they soon removed from their station... the encampment on the Mamoré was abandoned also: shortly after they fell back to S. Pedro: the Spaniards then returnrd to S. Cruz, and the expedition was broken up. The Portuguese then withdrew from the left shore." In Southern, Robert – History of Brazil, part third, London, 1819, p. 584.
- "... disease [caused by tropical conditions and the use of biological warfare by the Portuguese, according to the Spanish commander] and desertion had trimmed Verdugo [the Spanish Governor of Santa Cruz de la Sierra]’s levies from 610 to 303 by the time they reached San Pedro [head of the missions in Moxos, Bolivia, to where the Spanish remnants retreated]. (...) after two months on the Guaporé, the governor returned to Santa Cruz [Bolivia], leaving behind a skeleton force (...). In 1763 Moura retired from Mato Grosso the victor. He had advanced to the Guaporé [and beyond it, occupying Spanish territory in the left bank of this river until the end of the war: the territory of the Missions of S. Miguel and S. Martin, main sources of supply to the Spanish army.], fortified Portuguese positions on the river, and remained in the field as his rival retired. Moura’s service earned him a hero’s welcome from his commanders, a Knighthood, and eventually the office of Viceroy of Brazil." In Block, David – Mission Culture on the Upper Amazon: native Tradition, Jesuit enterprise and Secular Policy in Moxos, 1660–1880, University of Nebraska Press, 1994, p. 51.
- "During its progression [through the Rio Negro valley, the Spanish] advancement was beyond San Carlos, since the Spaniards had managed to occupy the posts of Marabitanas and San Gabriel, from which they were dislodged by the Portuguese, who fortified them, under the German captain Felipe [Phillip Sturm]. They were armed with cannons brought by the Spanish commission of limits. (...)" In Ojer, Pablo- La Década Fundamental en la Controversia de Límites entre Venezuela y Colombia, 1881-1891 (in Spanish), Academia Nacional de la Historia, 1988, p. 292.
- "São Gabriel was founded during the Portuguese conquest in 1763, when a fort was built...", in United States Army Corps of Engineers- Report on Orinoco-Casiquiare-Negro Waterway. Venezuela-Colombia-Brazil, July 1943, Vol. I, 1943, p. 15.
- "(...). In this 'race for the Rio Grande [territory]', the border of Rio Pardo was the only one who resisted the Spanish invasion, thanks to Barreto Pereira Pinto courage and, above all, Francisco Pinto Bandeira, which shattered the army of captain Antonio Cattani on January 1, 1763. Pinto Bandeira, with only 230 dragoons and adventurers of St. Paul, fell like a hurricane over the 2,500 enemy soldiers. 'Never saw this territory such a stampede.' (...). Cattani’s troops disbanded in panic. The commander, no time to put on the uniform, fled in underwear." In Barbosa, Fidélis D. – História do Rio Grande do Sul, Edições Est, 4th edition, Porto Alegre, 1976, p. 60.
- Flores, Moacyr- Dicionário de história do Brasil, Edipucrs, 2004, p. 80. ISBN 9788574302096
- "In January 1762, Spain opened hostilities with England [and against Portugal on 5 May 1762]. However, the effects were very different from those expected. (…)The outcome: the Loss of Havana and Manila [and most of the Rio Negro Valley in North Brazil] while our army engaged an unfortunate ground campaign against Portugal. Only the conquest of Colónia do Sacramento by Pedro Cevallos, from Uruguay, put a positive note on the Spanish side, but however, had no influence on subsequent agreements that ended the war." In Álvarez, Manuel Fernàndez- España Y Los Españoles En Los Tiempos Modernos, Universidad Salamanca, Spain, 1979, p. 439.
- Marley, David- Wars of the Americas: a chronology of armed conflict in the New World, 1492 to the present, vol. II, ABC-CLIO, USA, 2008, p. 449 and p. 450
- Bento, Cláudio Moreira- Brasil, conflitos externos 1500-1945 (electronic version), Academia de História Militar Terrestre do Brasil, chapter 5: As guerras no Sul 1763–77.
- Ricardo Lesser- Las Orígenes de la Argentina, Editorial Biblos, 2003, see chapter El desastre", see pp. 63–72.
- Bento, Cláudio Moreira- Rafael Pinto Bandeira in O Tuiuti, nr. 95, Academia de Historia Militar Terrestre do Brasil, 2013, pp. 3–18.
- "The Spaniards, having failed the campaign of Portugal, had to return Colonia del Sacramento, renounce claims on their fishing rights in Newfoundland, recognize the legality of the British settlements on the coast of Honduras, cede Florida to England, and confirm all the privileges that British commerce held before the war started." In Tandeter, Enrique (coordinator: Germán Carrera Damas – Historia General de América Latina: processos americanos hacia la redefinición colonial (in Spanish), vol. 4, UNESCO, 2000, p. 22.
- "The army was in no better shape. Only 8,000 effective [Portuguese] soldiers stood in the face of the coming Spanish onslaught. They wore 'rags and patches' and begged in the streets, as they received little or no pay from the central government." In Speelman, Patrick and Danley, Mark – The Seven Year’s War: Global Views, 2012, p. 436.
- "The British troops which embarked for Lisbon under their veteran commander consisted of 7, 104 officers and men of al arms [official figures when boarding in Britain]. This force had been dispatched In consequence of the threatening attitude of France and Spain towards Portugal, whose monarch had declined to enter into an alliance with the above two powers in order to 'curb the pride of the British nation which aspired to become despotic over the sea'." In Dalton, Charles- George The First's Army, 1714–1727, Vol. II, 1912, p. 31
- "All told the British forces in Portugal numbered roughly 7,000 men." In Speelman, Patrick and Danley, Mark – The Seven Year’s War: Global Views, 2012, p. 440.
- "A Campaign won without the major casualties of battle or incurring many losses other than those of sickness." In Journal of the Society for Army Historical Research, vol. 59, London, 1981, p. 25
- "British casualties were light overall – there were fourteen combat deaths compared to 804 from other means..." In Speelman, Patrick and Danley, Mark – The Seven Year’s War: Global Views, 2012, p. 448
- "Disappointed, facing incredible resistance and losing everything in the field, the Spaniards abandoned the fight and left behind twenty-five thousand men ..." In Henry, Isabelle – Dumouriez: Général de la Révolution (1739–1823), L'Harmattan, Paris, 2002, p. 87.
- Eduard Hay, British ambassador in Portugal (letter to the 2nd Earl of Egremont, 8 November 1762) reported a total of 30,000 Franco-Spanish casualties during the first two invasions of Portugal (half of them deserters, many of whom became prisoners), representing almost three quarters of the initial invading army. See British Scholar C. R. Boxer in Descriptive List of the State Papers Portugal, 1661–1780, in the Public Record Office, London: 1724-1765, Vol II, Lisbon, Academia das Ciências de Lisboa, with the collaboration of the British Academy and the P.R.O., 1979, p. 415. See also COSTA, Fernando Dores- Nova História Militar de Portugal , Círculo de Leitores, Vol. II, Coordinator: António Hespanha, 2004, p. 358, footnote 280.
- "Preparations the Spanish Government made for war after signing the compact with France focused more on Portugal than the colonies. (...)", In Greentree, David – A Far-Flung Gamble – Havana 1762, Osprey Publishing, Oxford, 2010, p. 30.
- "This operation was without doubt the greatest mobilisation of troops on mainland Spain throughout the whole eighteenth century, and the figures themselves bear witness to the government's interest in the operation...and meant leaving the rest of mainland Spain largely unguarded...by way of comparison, the battle of Almansa of 1707...involved a Spanish-French army of over 25,000 men...while the famous attack on Algiers in 1775 involved a mobilisation of little more than 19,000 infantry and cavalry men..." in Enciso, Agustín González (Spanish) – "Mobilising Resources for War: Britain and Spain at Work During the Early Modern Period", Eunsa, Ediciones Universidad de Navarra, S.A., Spain, 2006, p. 159, ISBN 9788431323844.
- "In 1762, England declares war on Spain; helps Portugal to defeat the Spanish invasion of that kingdom and captures Havana and Manila." In Singleton, Esther - The World's great events: an indexed history of the world from earliest times to the present day , Vol. V, P. F. Collier, New York, 1916, p. 1635.
- "After the Seven Years´ War, relations between them in 1763 were extremely bitter (...). Portugal could not at once forget the sudden invasion of her territory, as that of an English ally, by an army from Spain, when that Power decided to enter the recent international conflict, while Spain smarted from a sense of humiliation at the remembrance of the failure of that campaign." In Holmes, Vera Brown- Studies in the History of Spain in the Second Half of the Eighteenth Century, Vol. 15 and 16, The Dept. of history of Smith college, 1929, USA, p. 65.
- "...the militia of Portuguese peasants, whose intervention, coupled with the inaccessibility of the terrain, caused the failure of the Spanish invasion by the North [ Portugal] in 1762...", see Arenas, Mar García – Los Proyectos del General Dumouriez Sobre la Invasión de Portugal in El Equilibrio de los Imperios: de Utrecht a Trafalgar, Actas de la VIII Reunión Científica de la Fundación Española de Historia Moderna (Madrid, 2-4 de Junio de 2004), vol. II, Fundación Española de Historia Moderna, 2005, p. 548.
- "after the failed attempt of General Sarria, Charles III of Spain gave the command of the campaign to a younger and proud military, the count of Aranda...", In Huarte, Eulogio Zudaire- Don Agustín de Jáuregui y Aldecoa, Vol. I, Institución Príncipe de Viana, 1978, p. 45
- "This province [of Trás-os Montes] is not worth an attack in a war between Spain and Portugal; it is even dangerous for the Spaniards to penetrate into it, as they found to their cost in the late war; 40,000 men advanced to Chaves, Bragança and Miranda...and about a fourth of their number died there..." In Dumouriez, Charles – An Account of Portugal, as it Appeared in 1766 to Dumouriez, Lausanne (1775), and London (1797), p. 20.
- Ponce, José Luis Terrón – La Casaca y la Toga: Luces y sombras de la reforma militar en el reinado de Carlos III, Institut Menorquí d´Estudis, Mahón, 2011, La campaña de Portugal en 1762, pp.11–21, p. 13.
- "Under Count Von Lippe´s administration, the Portuguese army became an efficient and well-uniformed war machine and the strong Prussian influence of its mentor contributed to repulsing the expansionist attempts of the Spanish Crown." In Moreira, Maria and Veludo, Sérgio- Portuguese Studies Review, Volume 16, nr. 2, Baywolf Press, 2008, p. 83, ISSN 1057-1515.
- "... the main central attack on Portugal [second invasion] failed utterly...partly through the skilful measures of the prince of Lippe, who had been placed in charge of the Portuguese army, and strengthened by 7,000 British troops, partly through the bold partisan enterprises carried out against their line of communications by General Burgoyne [and the guerrillas]...But mainly the invasion failed through the absolute lack of munitions and food; the Portuguese – as was their wont – had swept the country side clean [a deadly scorched earth strategy], (...). After starving for some weeks in a roadless wilderness, the Spanish army retired into Estremadura [Spain] in a sad state of dilapidation. Next spring Charles III sued for peace. " in Journal of the Royal United Service Institution, Whitehall Yard, Vol. 63, W. Mitchell, United Kingdom, 1918, p. 196.
- "As soon as the enemy began to retire upon Castello Branco, Major-general Fraser was sent…to attack his rear...General Burgoyne advanced [he reoccupied Vila Velha de Ródão]… while General Townsend occupied Penamacor and Monsanto…the Count d`Aranda kept his Head-quarters at Castello Branco… Lippe, with his small army, determined to attack this force…and Aranda retreated at leisure, leaving his sick and wounded in the hospital at Castello Branco, with a letter, recommending them to the attention of the allied army…On the 15th of November, therefore, the whole of their force retired into Spanish Estremadura…and Portugal, with the exception of Almeida and Chaves, was freed from the enemy." In The Royal Military Chronicle, vol V, London, 1812, pp. 52, 53.
- in Arquivo Nacional, Vol. 11, Edições 522-573, Empresa Nacional de Publicidade, 1942, p. 319
- "... Spain ordered 40,000 men to march into Portugal (page 247) ... The Spanish forces, when they arrived at the frontier, were reduced to 25,000 men, (...). This war, which might have crushed Portugal, gave it a degree of vigour and elasticity ... and produced a military spirit (page 254) ...", in Dumouriez, Charles – An Account of Portugal, as it Appeared in 1766 to Dumouriez, Lausanne (1775) and London (1797).
- In Danley Mark and Patrick Speelman – The Seven Year’s War: Global Views, Brill, 2012, chapter 16, p. 452.
- In Danley Mark and Patrick Speelman- The Seven Year’s War: Global Views, Brill, 2012, chapter 16, p. 521".
- "The first place which the enemy attempted to take was Marvão. This small town was attacked by a corps of 4,000 or 5,000 men, but the firmness of Captain Brown not only saved the place, but obliged the enemy to retire with considerable loss. Ouguela, another small fort, was next attempted, but here the bravery of Captain Braz de Carvalho and his small garrison was equally conspicuous, as the enemy were driven from before the place with considerable loss and obliged to abandon the attempt. The resistance which the Spaniards met with in these...places, had a visible effect upon their movements, and convinced them...", in The Royal Military Chronicle, vol V, London, 1812, p. 53.
- 700 regular infantry troops, 200 dragoons, 1,800 militiamen and 1200 Indians. See Marley, David- Wars of the Americas: a chronology of armed conflict in the New World, 1492 to the present, vol. II, ABC-CLIO, USA, 2008, p. 441.
- "The 400 Portuguese infantry men, 40 troopers, 32 gunners, 230 militiamen ... are reinforced from Rio de Janeiro by a 10-ship convoy ... although conveying only 65 soldiers... ", in Marley, David- Wars of the Americas: a chronology of armed conflict in the New World, 1492 to the present, vol. II, ABC-CLIO, USA, 2008, p. 441-442.
- " [Portuguese colonel] Osório built a small fort which he called Santa Teresa, where he took shelter with 400 men and little artillery (January 1763). Next April, Ceballos, who had gathered in Maldonado a well provisioned army of more than 3,000 men with much artillery, invested the Lusitanian position. After a weak resistance, Osório surrendered with the remaining 130 men. All the other had deserted." In Instituto Histórico e Geográfico do Rio Grande do Sul- Revista do Instituto Histórico e Geográfico do Rio Grande do Sul, Edições 132-134, Brazil, 1998, p. 12.
- "...Osório , arrives at Castilhos on the shores of Merín Lagoon with 400 men of the Dragoon Regiment of rio Pardo, 10 small artillery pieces, plus a work column, to commence construction ... of a border keep to be called Fort Santa Tereza...", In Marley, David- Wars of the Americas: a chronology of armed conflict in the New World, 1492 to the present, vol. II, ABC-CLIO, USA, 2008, p. 441.
- "Four days later, the small fort of San Miguel fell into the hands of Cevallos, abandoned by the garrison of 30 men which stayed there under cap. João Teixeira.", In Instituto Histórico e Geográfico do Rio Grande do Sul- Revista do Instituto Histórico e Geográfico do Rio Grande do Sul, Edições 132-134, Brazil, 1998, p. 12.
- "In the whole region of the Rio Grande, the Portuguese government did not have more than 1,000 soldiers, including regular and militia troops, spread over several trims." In Instituto Histórico e Geográfico do Rio Grande do Sul- Revista do Instituto Histórico e Geográfico do Rio Grande do Sul, Edições 132-134, Brazil, 1998, p. 12.
- "While the Spanish army advanced along the coast, fully reaching their goals, another enemy column, consisting of five hundred militiamen from the Corrientes Province and about 2,000 Guaranis came from the Misiones Orientales against Rio Pardo, under lieutenant colonel Antonio Cattani and fortified next to the stream of Santa Barbara..." in Vellinho, Moysés- Fronteira, Editora Globo, 1975, p. 105.
- Branco, José-Obras do Barão do Rio Branco, vol. VI, Ministério das Relações exteriores, Brazil, p.3.
- Arenas, Mar García- Los Proyectos del General Dumouriez Sobre la Invasión de Portugal in El Equilibrio de los Imperios: de Utrecht a Trafalgar, Actas de la VIII Reunión Científica de la Fundación Española de Historia Moderna (Madrid, 2-4 de Junio de 2004), vol. II, Fundación Española de Historia Moderna, published in 2005, pp. 537–550.
- Barrento, António- Guerra Fantástica, 1762: Portugal, o Conde de Lippe e a Guerra dos Sete Anos. Lisboa, Tribuna, 2006.
- Bento, Cláudio Moreira- Brasil, conflitos externos 1500-1945 (electronic version), Academia de História Militar Terrestre do Brasil, chapter 5: As guerras no Sul 1763-77
- Bento, Cláudio Moreira- Rafael Pinto Bandeira in O Tuiuti, Nº 95, Academia de Historia Militar Terrestre do Brasil, 2013
- Black, Jeremy- The Cambridge Illustrated Atlas of Warfare: Renaissance to Revolution, 1492–1792, 1996. ISBN 9780521470339
- Dumouriez, Charles- An Account of Portugal, as it Appeared in 1766 to Dumouriez, Lausanne (1775), and London (1797).
- EXPEDICIÓN A LA COLONIA DEL SACRAMENTO (1776 - 1777)
- Francis, Alan David. The Campaign in Portugal, 1762 in Journal of the Society of Army Historical Research, Vol. 59, nr. 237 (pp. 25–43). Society of Army Historical Research. London, 1981.
- Guerras entre España y Portugal en la cuenca del Río de la Plata
- Gipson, Lawrence- The British Empire before the American Revolution: the great war for the Empire: the culmination, 1760–1763, Vol VIII. Knopf, 1954.
- Lesser, Ricardo- Las Orígenes de la Argentina, Editorial Biblos, 2003, chapter "El desastre" (pp. 63–72).
- Marley, David- Wars of the Americas: a chronology of armed conflict in the New World, 1492 to the present, vol. II, ABC-CLIO, USA, 2008.
- Ponce, José Tertón - La Casaca y la Toga: Luces y sombras de la reforma militar en el reinado de Carlos III. Institut Menorquí d'Estudis, Mahón, 2011, La campaña de Portugal en 1762, pp.11-21.
- PRIMERA GUERRA DEL III PACTO DE FAMILIA (1762–1763)
- Sandler, Stanley- Ground Warfare: An International Encyclopedia, Volume 1, 2002. ISBN 9781576073445
- Simms, Brendan- Three Victories and a Defeat: The Rise and Fall of the First British Empire, 2008. ISBN 9780465013326
- Speelman, Patrick and Mark, Danley- The Seven Year’s War: Global Views. Brill, 2012, chapter 16: Strategic illusions and the Iberian War of 1762 (pp. 429–460). ISBN 978-90-04-23644-8.
- Úrdañez, José Luis Gómez- Víctimas Ilustradas del Despotismo. El Conde de Superunda, Culpable y Reo, ante el Conde de Aranda. , Universidad de la Rioja, 2009, (part of the investigation project El Imperio Español, Desde la Decadencia a la España Discreta..., HAR 2009-13824)
- Schaumburg-Lippe, William- Mémoire de la Campagne de Portugal de 1762. 1770.