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The 18th-century Antecedents of the Concert of Europe II: The Quadruple Alliance of 1718

By: Randall Lesaffer

With the Triple Alliance of 4 January 1717 (30 CTS 65) Britain and France affirmed their adherence to the peace settlement of Utrecht-Rastatt-Baden. Both great powers rejected—for the time being—the option of exploiting the outstanding differences between the Emperor Charles VI (1685–1740), Spain, and Savoy over Italy to their own advantage. They chose to join efforts to try to settle these differences and thus finalize the work of Utrecht. Already during the final months of 1716, the two architects of the Triple Alliance, the British James Stanhope (1673–1721) and the French Guillaume Dubois (1666–1723), were trying to draw the three contending powers into a compromise.

The Franco-British peace plan rested on three pillars. Firstly, both the emperor and Spain would accept the settlement of Utrecht whereby they would mutually cede their claim to one another’s thrones and territories. Secondly, all parties would confirm the succession in Britain and France, thus adding a new guarantee for the cession of his rights to the French throne by the Spanish King Philip V (1683–1746) and securing the position of the regent, Duke Philip of Orleans (1674–1723). Thirdly, Savoy would cede Sicily, which it had obtained under the Utrecht settlement, to the Emperor, who would cede Sardinia to Savoy in return. Spain would waive its right of return of Sicily in case of the extinction of the house of Savoy in the male line, which it had reserved under the Utrecht settlement (Treaty between Savoy and Spain of 10 June 1713, Article 2, 28 CTS 203).

The peace plan clashed with the ambitions of the Spanish royal couple and their chief minister, Cardinal Giulio Alberoni (1664–1752). Whereas Philip V had not given up the dream of restoring the Spanish possessions in Italy and particularly coveted the return of Sicily, his wife Elisabeth Farnese (1692–1766) from the house of Parma-Piacenza had ambitions of her own for her son Don Carlos (1716–1788), whose place in the line of succession to the Spanish crown came after the sons Philip V had from his first marriage to Maria Luisa of Savoy (1688–1714). The royal coupled hoped, through the dynastic rights of Elisabeth, to obtain the duchies of Parma and Piacenza, and possibly the Grand-Duchy of Tuscany for Don Carlos.

For Madrid, the Franco-British peace proposal contained nothing but the confirmation of Philip’s hold on the Spanish throne by the Austrian Habsburgs. Whereas at the very end of 1716, the imperial government signalled its assent to the plan, Spain remained deaf to the proposals. Over the early months of 1717, it plotted action. The Spanish government felt the time was propitious. It had little faith in the sustainability of the entente between Versailles and London. At the court of Versailles, there was a strong pro-Spanish faction which opposed the regent and Dubois and pleaded for a Franco-Spanish Bourbon alliance. Moreover, Spain counted on the merchant interest in London to stop Britain from a rupture with Madrid as this would damage trade in the Mediterranean as well as in the Americas. Finally, the timing for an attack on the Habsburg Monarchy in Italy was auspicious now that the imperial troops were fighting the Ottoman Empire in the Balkans.

In August 1717 Madrid landed its blow and invaded Sardinia. The Austrian defences crumbled and the island was overrun. In the rounds of negotiations which followed over the autumn, winter, and spring of 1717–1718, the two main Utrecht powers moved towards concessions for Spain. In the newly emerging proposals the succession to Parma, Piacenza, and Tuscany by Don Carlos in case of the extinction of the lines of their respective rulers was promised and guaranteed. This did not suffice for the Spanish king and Cardinal Alberoni. In June 1718, Madrid again derided the British diplomatic efforts and the pressure which came from the Franco-British entente, this time by sending a large fleet to Sicily and invading the island.

Philip V’s bold move backfired. On 18 July 1718, Britain and France finalized and accepted the text of new treaty at London. The treaty articulated the peace plan in detail and invited Austria, Spain, and Savoy to adhere within three months. Three days later, on 21 July 1718, the Emperor Charles VI made peace with the Ottoman Empire at Passarowitz (30 CTS 341). While this raised some doubt at Vienna over the need to accept the Franco-British plan, in early August the deal was done and on 2 August 1718, Charles VI acceded to the treaty (30 CTS 415). It thus became known as the Quadruple Alliance because it was intended to include the Dutch Republic. The Republic, however, refused to accede so as to avoid jeopardizing its trade with Spain. The secret articles, which were confirmed at the time of Austria’s accession, provided for a new period of three months for Spain and Savoy to accede. In case they did not, the allies promised military aid to the Austrian Habsburg Monarchy to reconquer Sardinia and Sicily and to enforce the agreement on Italy. In case Spain or Savoy declared war on one of the allies, the others would also enter into open war with them and fight it until full implementation of the treaty was reached (Secret Article 2). Meanwhile, in November 1718, Savoy acceded to the alliance (30 CTS 467).

But events in the theatre of war overtook the timing of the treaty. In June of 1718, a British fleet had already entered the Western Mediterranean. On 11 August, a major naval engagement took place between the British and Spanish fleets at Capo Passero, the south-eastern tip of Sicily near Syracuse. The Spanish suffered a crushing defeat, thus drowning Philip’s and Alberoni’s dream of restoring the Spanish Empire in Italy. Nevertheless, Madrid refused to acknowledge defeat and the conflict escalated into open war, first with Britain and then, in early 1719, with France, leading to a French invasion of Spain in the spring of that year. In the end, it took until the end of the year for Philip V to bow to the inevitable. In December 1719, he sacked Alberoni and thus opened the door to compromise. In early 1720, Spain acceded to the Quadruple Alliance and affirmed the settlement with regard to Italy (Accession of 17 February 1720, 31 CTS 149). The succession to Parma, Piacenza, Tuscany, and some other territories was guaranteed to Don Carlos. The emperor, as suzerain overlord over the old kingdom of Italy, promised the investiture to the Spanish prince and guaranteed that garrisons of Swiss soldiers would be placed in some key fortresses (Quadruple Alliance, Article 5).

Through the establishment of the Quadruple Alliance, the two leading powers of Europe created a diplomatic and legal instrument to finalize the pan-European peace work started at Utrecht. In essence, theirs was a bilateral alliance—with the largely symbolic participation of the Dutch Republic providing just some semblance of being a wider European alliance—to impose their will on some other powers of Europe. But this narrow platform did not stop them from taking the moral high ground and claiming to act, and pressuring others to accept their actions, in the name of the common interest of Europe. The catchphrase used in the Quadruple Alliance for that common interest was that of ‘public peace and quiet’ or ‘public tranquillity’, for which the balance of power and the safeguarding of the successions that had been agreed at Utrecht were considered crucial. By referring to the higher interest of Europe, the two, and after the accession of Vienna, the three leading powers of Europe pretended to act collectively in the name of Europe while imposing their will and interests on the fourth, recalcitrant and revisionist, power. To that extent, the Quadruple Alliance may indeed be considered as a distant and unintended predecessor to the idea of collective security and the 19th-century concert of Europe, in which the leading role of the great power was foundational. Moreover, the plan to introduce neutral Swiss soldiers in Parma, Piacenza, and Tuscany to observe and guarantee the implementation of part of the peace plan can be seen as a distant antecedent to a key instrument of modern, collective peace-keeping.


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