The War of the Quadruple Alliance[a] was fought from 1717 to 1720 by Spain and the Habsburg Monarchy,[1] with the latter being joined in 1718 by Great Britain, France, and Savoy,[2] and in 1719 by the Dutch Republic.

[3] Caused by Spanish attempts to recover territories in Italy ceded in the 1713 Peace of Utrecht, most of the fighting took place in Sicily and Spain, with minor engagements in North America.

[3] Under the 1713 Peace of Utrecht that ended the War of the Spanish Succession, Spain ceded possessions in Italy and Flanders to Austria, and Sicily to Savoy.

However, a series of deaths in the French royal family between 1713 and 1715 made him heir presumptive to the five year old Louis XV, and he now cast doubts on this renunciation.

Emperor Charles VI also refused to accept this principle, as well as delaying implementation of the Barrier Treaty in the newly acquired Austrian Netherlands, an objective for which the Dutch Republic had effectively bankrupted themselves.

As neither Savoy nor Austria possessed significant navies, the most obvious targets were the islands of Sardinia and Sicily, an ambition that aligned with the Italian dynastic claims of Elizabeth Farnese.

They met little opposition; Austria was engaged in the 1716–1718 Austro-Turkish War, while France and the Netherlands needed peace to rebuild their shattered economies.

[10] Attempts to resolve the situation through diplomacy failed and in June 1718, a British naval force arrived in the Western Mediterranean as a preventive measure.

Austria signed the July 1718 Treaty of Passarowitz with the Ottoman Empire, and on 2 August, joined Britain, France, and the Dutch in the Quadruple Alliance, which gave its name to the war.

The Duc d'Orléans ordered a French army under the Duke of Berwick to invade the western Basque districts of Spain in April 1719, still under the shock of Philip V's military intervention against them.

In early 1719 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".

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.

[16][17] Displeased with his kingdom's military performance, Philip dismissed Alberoni in December 1719, and made peace with the allies with the Treaty of The Hague on 17 February 1720.