War of the Quadruple Alliance The War of the Quadruple Alliance ( 1718 – 1720 ) was a result of the ambitions of King Philip V of Spain , his wife , Elisabeth Farnese , and his chief minister Giulio Alberoni to retake territories in Italy and to claim the French throne . It saw the defeat of Spain by an alliance of Britain , France , Austria ( then a State of the Holy Roman Empire ) , and the Dutch Republic . Savoy later joined the coalition as the fifth ally . Although fighting began as early as 1717 , war was not formally declared until December 1718 . It was brought to an end by the Treaty of The Hague in 1720 . Causes . Charles II of Spain died in 1700 leaving no heirs to succeed him . By his will , he named Philip , Duke of Anjou , grandson of Louis XIV of France , as his successor . This led to the War of the Spanish Succession ( 1701 - 1714 ) , at the end of which Philip , Duke of Anjou , was recognized as King Philip V of Spain , but on the condition that the French and Spanish crowns would never be united . By the Treaty of Utrecht ( 1713 ) , Spain lost all its possessions in Italy and the Low Countries . The Spanish Netherlands , Duchy of Milan , Naples and Sardinia were given to Emperor Charles VI , emperor of the Habsburg - ruled Austria , while Sicily was awarded to the Duke of Savoy and Prussia received the Spanish Gueldres . These lands had been under Spanish Habsburg control for nearly two centuries , and their loss was perceived as a great blow to the country in both practical and prestige terms . However , the first priority for Spain was the restoration of the country after 13 years of war , which had in part been fought on Spanish territory . The main architect of this operation was Giulio Alberoni . Alberoni was an Italian cardinal and steward of the archbishop of Plasencia . In 1714 , Alberoni had arranged the marriage of the widowed Philip V to the 21 year - old Italian Elisabeth Farnese . In the process , Alberoni became the personal adviser of the new queen . In 1715 , Alberoni became prime minister , stabilized the Spanish economy and reformed finances . He also initiated the rebuilding of the Spanish fleet ( with 50 ships of the line built in 1718 alone ) and reformed the army . In 1717 , Alberoni became a cardinal in the Roman Catholic Church . The Queen , who had several dynastic claims to advance in Italy , stimulated the Italian ambitions of her husband and their sons , supported by Alberoni . In France , Louis XIV died in 1715 leaving only one infant great - grandchild , Louis XV , as his successor , with Philip V , the only surviving grandchild of Louis XIV , and his sons were excluded from succession to the crown of France by the Treaty of Utrecht . Philip V nevertheless claimed the French throne , in the event of the death of the infant Louis . Opposition to Philip ' s ambitions led France ( where Louis XIV ' s nephew , the Duke of Orléans , served as regent ) , Great Britain , and the Dutch Republic , to join together in the Triple Alliance on 4 January 1717 . Britain , in particular , had become very concerned by Spanish ambitions in the Mediterranean Sea and Russian expansion in the Baltic and dispatched fleets to both as a preventative measure . The French navy was badly weakened from the recent war , and could not offer much support . Outbreak of conflict . Later in the year , to strengthen the Treaty of Utrecht , Britain , France and Austria contemplated ceding Sicily to the Holy Roman Emperor Charles VI . This arrangement displeased Spain , who wanted to recover the island . < br > In August 1717 Philip began hostilities against Austria by invading the island of Sardinia , taking advantage of the fact that Austria was tied up in the Austro - Turkish War of 1716 - 18 . A fleet of 100 transport ships , protected by 15 warships , carried 9 , 000 men under command of the Marquis of Lede was assembled . It sailed from Barcelona to Sardinia , which was subdued by November 1717 . The initial Austrian reaction to this invasion was limited , as the Austrian Supreme Commander Prince Eugene of Savoy wanted to avoid a major war in Italy as long as the conflict in the Balkans continued , soaking up Austrian troops and resources . Finally , on 21 July 1718 , the Treaty of Passarowitz ended the war with the Ottoman Empire and on 2 August , this led to the formation of the Quadruple Alliance , with the Emperor now joining the Triple Alliance . Wider war . Meanwhile , in July 1718 the Spanish , this time with 30 , 000 men again led by the Marquis of Lede , had also invaded Sicily , which had been awarded to the Duke of Savoy . They took Palermo on 7 July and then divided their army in two . De Lede followed the coast to besiege Messina between 18 July and 30 September , while Montemar conquered the rest of the island . The French , Austrians , and British now demanded Spanish withdrawal from Sicily and Sardinia . The attitude of Victor Amadeus II of Savoy was ambiguous , as he agreed to negotiate with Cardinal Alberoni to form an anti - Austrian alliance . On 11 August , at the Battle of Cape Passaro , a British fleet , led by Sir George Byng , effectively eliminated the Spanish fleet stationed off Sicily . This was followed in the autumn by the landing of a small Austrian army , assembled in Naples by the Austrian Viceroy Count Wirich Philipp von Daun , near Messina to lift the siege by the Spanish forces . The Austrians were defeated in the First Battle of Milazzo on 15 October , and only held a small bridgehead around Milazzo . In 1718 , Cardinal Alberoni began plotting to replace the Duc d ' Orléans , regent to the 5 - year King Louis XV of France , with Philip V . This plot became known as the Cellamare Conspiracy . After the plot was discovered , Alberoni was expelled from France , which declared war on Spain . By 17 December 1718 , the French , British , and Austrians had all officially entered the war against Spain . The Dutch would join them later , in August 1719 . 1719 . The Duc d ' Orléans ordered a French army under the Duke of Berwick to invade the Basque provinces of Spain in April 1719 . This army met very little resistance , but was forced back by heavy losses due to disease . A second attack in Catalonia suffered the same fate . In the Americas , the French were more successful and took Pensacola in Florida . In Sicily , the Austrians started a new offensive under Count Claude Florimond de Mercy . They first suffered a defeat in the Battle of Francavilla ( 20 June 1719 ) . But the Spanish were cut off from their homeland by the British fleet and it was just a matter of time before their resistance would crumble . Mercy was then victorious in the second Battle of Milazzo , took Messina in October and besieged Palermo . It was also in 1719 that the Irish exile , the Duke of Ormonde , organized an expedition with extensive Spanish support to invade Britain and replace King George I with James Stuart , the Jacobite " Old Pretender " . However , his fleet was dispersed by a storm near Galicia in 1719 , and never reached Britain . A small force of 300 Spanish marines under George Keith , tenth Earl Marischal did land near Eilean Donan , but they and the highlanders who supported them were defeated at the Battle of Eilean Donan in May 1719 and the Battle of Glen Shiel a month later , and the hopes of an uprising soon fizzled out . In retaliation for this attack , a British fleet captured Vigo and marched inland to Pontevedra in October 1719 . This caused some shock to the Spanish authorities as they realized how vulnerable they were to Allied amphibious attacks , with the potential to open up a new front away from the French frontier . The French captured the Spanish settlement of Pensacola in Florida in May 1719 , pre - empting a Spanish attack on South Carolina . While Spanish forces retook the town in August 1719 , it fell to the French again towards the end of the year and they destroyed the town before withdrawing . A 1 , 200 strong Spanish force set out from Cuba to take the British settlement of Nassau in the Bahamas . After taking a large amount of plunder they were eventually driven off by the local militia . Peace . Displeased with his kingdom ' s military performance , Philip dismissed Alberoni in December 1719 , and made peace with the allies at the Treaty of The Hague on 17 February 1720 . In the treaty , Philip was forced to relinquish all territory captured in the war . However , their eldest son ' s right to the Duchy of Parma and Piacenza after the death of Isabella ' s childless half - cousin , Antonio Farnese , was recognized . France returned Pensacola and the remaining conquests in the north of Spain in exchange for commercial benefits . Included in the terms of this treaty , the Duke of Savoy was forced to exchange his throne in Sicily for that of the less important Kingdom of Sardinia . Ironically , it was the less important Kingdom of Sardinia that would later unify Italy in the nineteenth century . Legacy . The war provided a unique example during the eighteenth century when Britain and France were on the same side . It came during a period between 1716 and 1731 when the two countries were allies . Spain would later join with France in the Bourbon Compact , and the two would become continual enemies of the British . The war also demonstrated the growing seapower of Britain , and the successful deployment of the Royal Navy in the Mediterranean Sea .