The 1748 Treaty of Aix-la-Chapelle, sometimes called the Treaty of Aachen, ended the War of the Austrian Succession, following a congress assembled on 24 April 1748 at the Free Imperial City of Aachen.
The two main antagonists in the war, Britain and France, opened peace talks in the Dutch city of Breda in 1746. Agreement was delayed by British hopes of improving their position; when this failed to occur, a draft treaty was agreed on 30 April 1748. A final version was signed on 18 October 1748 by Britain, France, and the Dutch Republic.
The terms were then presented to the other belligerents, who could either accept them or continue the war on their own. Austria, Spain, and Sardinia had little choice but to comply, though the terms were favorable for Spain who took land from Austria in Italy, and in defeating the British invasion in South America, were able to renew a monopoly in the supply of slaves to Spanish America.
The treaty largely failed to resolve the issues that caused the war, while most of the signatories were unhappy with the terms. Maria Theresa resented Austria's exclusion from the talks, and blamed Britain for forcing her to accept concessions, while British politicians felt they had received little benefit for the financial subsidies paid to her. These issues, combined with other factors, led to the strategic realignment known as the Diplomatic Revolution, and the outbreak of the Seven Years' War in 1756.
Franco-British negotiations began at Breda in August 1746 but were deliberately delayed by the Duke of Newcastle, who controlled British foreign policy. The death of Philip V of Spain in July 1746 seemed an opportunity to break the Bourbon alliance, while Newcastle hoped the Orangist revolution would revitalise the Dutch war effort, and allow the Allies to recover the Austrian Netherlands. Both assumptions proved incorrect; Spanish policy remained largely unchanged, the Dutch States Army collapsed, and Newcastle later berated himself for his "ignorance, obstinacy, and credulity".
However, despite French victories in Flanders, the impact of the British naval blockade was such that throughout 1746, Finance Minister Machault repeatedly warned Louis XV of the impending collapse of their financial system. The position became critical after the Second Battle of Cape Finisterre in October 1747, as the French Navy was no longer strong enough to protect their merchant convoys.
Maria Theresa made peace with Bavaria in April 1745, then with Prussia in December; only British financial subsidies kept Austria in the war thereafter. At a conference in December 1747, Austrian ministers agreed 'the worse peace is preferable to starting another campaign', and drew up proposals for ending the stalemate in Italy. They agreed to withdraw Austrian troops from the Duchy of Modena and Republic of Genoa, confirm Spanish control of Naples, and provide territorial concessions that would provide Infante Philip of Spain with an Italian state.
In November, Britain signed a convention with Russia for the supply of troops and in February 1748, a Russian corps of 37,000 arrived in the Rhineland. Lack of progress in Flanders and domestic opposition to the cost of subsidising its allies meant Britain was also ready to end the war. Both France and Britain were prepared to impose terms on their allies if needed, but preferred to avoid dropping them by making a separate peace treaty.
On 30 April 1748, France, Britain, and the Dutch Republic signed a preliminary treaty which included the return of the Austrian Netherlands, the Dutch Barrier forts, Maastricht and Bergen op Zoom. They also guaranteed the Austrian cession of Silesia to Prussia, as well as the Duchies of Parma, and Guastalla to Philip of Spain. Faced with this, Austria, Sardinia, Spain, Modena and Genoa acceded to the treaty in two separate documents finalised on 4 December 1748 and 21 January 1749 respectively.
All signatories accept the Pragmatic Sanction of 1713;
Austria recognises the Prussian acquisition of Silesia
Austria cedes the Duchies of Parma, Piacenza and Guastalla to Philip of Spain, second eldest son of Philip V of Spain and Elisabeth Farnese;
Austria cedes minor territories in Italy to Sardinia, including Vigevano;
Austria withdraws from the Duchy of Modena and Republic of Genoa, which regain their independence;
France withdraws from the Austrian Netherlands and returns the Dutch Barrier forts, Maastricht and Bergen op Zoom;
Britain and France exchange Louisbourg on Île-Royale for Madras in India;
Spain renews the Asiento de Negros (a monopoly contract to supply slaves to Spanish America) which was granted to Britain in the 1713 Treaty of Utrecht; Britain subsequently renounced this under the 1750 Treaty of Madrid, in return for £100,000;
Commission established to resolve competing claims between French and British colonies in North America. France also agrees to expel the Jacobite Prince of Wales, Charles Edward Stuart.