In the War of the Spanish Succession (1701–14), Portugal’s recent friends England and France fought on opposing sides. Although Peter initially sought to remain neutral, Portugal joined the Anglo-Austrian Grand Alliance in 1703 and provided a base for the archduke Charles (later Emperor Charles VI) to conduct his war for the Spanish throne. Then on December 27, 1703, the English envoy, John Methuen, concluded the treaty that bears his name, by which the exchange of port wine for English woolens became the basis for Anglo-Portuguese trade. Although the treaty of 1654 had secured great privileges for English merchants in Lisbon, neither it nor the treaties of 1642 and 1661, by which the traditional alliance was restored, had created trade. This was now done, and, with the wealth that soon poured into Lisbon from Brazil, the English merchants gained a commanding position in the trade of Portugal. The political treaties of 1703 proved less fruitful. The Portuguese general António Luís de Sousa, marquês das Minas, entered Madrid in 1706, but French and Spanish forces were victorious at Almansa in 1707, and in 1711 the French admiral René Duguay-Trouin sacked Rio de Janeiro. At the conclusion of the war, Portugal negotiated a peace treaty with France (April 1713), but peace with Spain was not concluded until 1715.

Portugal under Peter’s son John V (1706–50) attained a degree of prosperity unknown since the restoration of independence from Spain. The tax of a royal fifth levied on the precious metals and stones of Brazil gave the monarchy an independent source of wealth. The Cortes, which had met irregularly since 1640, was no longer summoned, and government was carried out by ministers appointed by the king. John V desired the absolute authority enjoyed by Louis XIV in France. John converted his wealth into papal and other dignities: the archbishop of Lisbon became a patriarch (1716); Pope Benedict XIV gave John the title “His Most Faithful Majesty” (1749); and royal academies, palaces, and libraries were inaugurated. But in his later years, his ministers proved inadequate, and the kingdom sank into stagnation.

On John’s death, his son Joseph (1750–77) appointed as minister Sebastião José de Carvalho e Melo (later conde de Oeiras and marquês de Pombal), who soon gained a complete ascendancy over the king and endeavoured to replace the stagnant absolutism with a more active type of despotism that, with some qualifications, deserves the epithet “enlightened.” Pombal’s full powers date from his efficient handling of the crisis caused by the disastrous Lisbon earthquake of November 1755, but even before this he had reformed the sugar and diamond trades, set up a national silk industry (1750), and formed one chartered company to control the sardine- and tunny-fishing industry of the Algarve and another to trade with northern Brazil. In 1756 he founded a board of trade with powers to limit the privileges enjoyed by the English merchants under the treaties of 1654 and 1661 and set up the General Company for Wines of Alto Douro to control the port wine trade. Industries for the manufacture of hats (1759), cutlery (1764), and other articles were established with varying success.

Pombal’s methods were arbitrary and his enemies numerous. His reform of the wine industry provoked a riot in Porto (1757) that was savagely repressed. However, his principal victims were the Jesuits, who were expelled in 1759 from all the Portuguese dominions, and the nobility, in particular José Mascarenhas, duque de Aveiro, and the Távora family (see Conspiracy of the Távoras), who were accused of an attack on the king (September 3, 1758), condemned, and executed (January 12, 1759). Having eliminated the Jesuits from the educational system, Pombal applied regalist principles in the reform of the University of Coimbra (1772) and the royal board of censorship (1768), which supervised the system of lower education from 1771.

While Pombal succeeded in modifying the ascendancy of the British merchants in Portugal, he invoked the English alliance in 1762 when Spain, prompted by the renewal of the Bourbon Family Compact with France, invaded Portugal. The Portuguese army was reformed by Wilhelm von Schaumburg-Lippe, and an English force was led by James O’Hara, 2nd Baron Tyrawley, and John Campbell, 4th earl of Loudoun. A peace treaty was signed in February 1763 at Fontainebleau. After Joseph’s death on February 24, 1777, his daughter Maria I (1777–1816), who had married Joseph’s brother and her uncle (Peter III), acceded to the throne; Pombal was dismissed (1777) and eventually found guilty on several charges. His successors made peace with Spain by the Treaty of San Ildefonso (1777).

The French revolutionary and Napoleonic wars

After the death of Peter III in 1786 and her eldest son Joseph in 1788, Maria I suffered from melancholia. In 1792 her mental instability increased following news of the radical phases of the French Revolution, and she ceased to reign. Her surviving son ruled in her name, formally became prince regent in 1799, and on her death became John VI (1816–26). In 1793 Portugal joined England and Spain against France, sending a naval division to assist the English Mediterranean fleet and an army to the Catalan front. The Peace of Basel (July 1795), by which Spain abandoned its allies, left Portugal still at war. Although subjected to pressure from the French Directory and from the Spanish minister, Manuel de Godoy, Portugal remained unmolested until 1801, when Godoy sent an ultimatum and invaded the Alentejo. By the Peace of Badajoz (June 1801), Portugal lost the town of Olivenza and paid an indemnity.

From the Peace of Amiens (1802) until 1807, Portugal was once more immune from attack, though it was subjected to continuous pressure to break off the English connection. Napoleon sought to close all continental ports to British ships, but Portugal endeavoured to maintain neutrality. The secret Franco-Spanish Treaty of Fontainebleau (October 1807) provided for Portugal’s eventual dismemberment by Napoleon I and Godoy. Already one of Napoleon’s generals, Andoche Junot, was hastening across Spain with a French army, and on November 27 the prince regent and the royal family and court embarked on a fleet lying in the Tagus River and were escorted by British vessels to Brazil; the court remained at Rio de Janeiro for 14 years. Junot declared the Braganças deposed, but his occupation of Portugal was challenged in August 1808 by the arrival of Sir Arthur Wellesley (later duke of Wellington) and 13,500 British troops in Mondego Bay. Winning the victories of Roliça (August 17) and Vimeiro (August 21), Wellington enabled his superiors to negotiate the Convention of Sintra (August 31), by which Junot was allowed to evacuate Portugal with his army.

A second French invasion (1808–09) led to Sir John Moore’s death at La Coruña, Spain, in January 1809 and the reembarkation of the British forces. In February William Carr (later Viscount) Beresford was placed in command of the Portuguese army, and in March a French force under Marshal Nicolas-Jean de Dieu Soult advanced from Galicia and occupied Porto. Wellesley returned to Portugal in April, drove Soult from the north, and, after his victory of Talavera de la Reina in Spain (July), withdrew to Portugal.

The third French invasion followed in August 1810 when Marshal André Masséna with Marshal Michel Ney and Junot entered Beira province. Defeated by Wellington at Bussaco (September 27) near Coimbra, the French found themselves facing the entrenched lines of Torres Vedras, north of Lisbon, where they wintered amid great privations. By the spring of 1811 they could only retreat, and on March 5 they began the evacuation of Portugal, harassed all the way by English and Portuguese attacks and crossing the frontier after a defeat at Sabugal (April 3).

Portugal and France made peace on May 30, 1814. Portugal was represented at the Congress of Vienna, but it played little part in the settlement. The series of Anglo-Portuguese treaties concluded between the years 1809 and 1817, however, was important insofar as it extended many of the conditions of the Anglo-Portuguese alliance to Brazil and had an influence on the future of Africa. England’s efforts to enlist Portuguese collaboration in suppressing the slave trade resulted in the treaty of January 22, 1815, and in the additional convention of 1817, by reason of which Portugal’s claims to a considerable part of Africa were formally recognized.