Congress of Aix-la-Chapelle (1818)

The Congress of Aix-la-Chapelle, held in the autumn of 1818 in Aachen (Aix-la-Chapelle in French), was a meeting of the Quadruple Alliance – Great Britain, Austria, Prussia, and Russia – to discuss and negotiate the withdrawal of Allied troops from occupied France following the Napoleonic Wars. It was one of a series of congresses held during the period of the Concert of Europe.

The primary focus was the complete evacuation of France, which had largely fulfilled the terms of the Second Treaty of Paris (1815), including payment of reparations. The Duke of Richelieu, representing France, successfully negotiated the early withdrawal of the Allied army of occupation. This was achieved in exchange for France's agreement to continue payments according to a revised schedule. France was formally readmitted into the Concert of Europe as a full member.

Beyond the French question, the Congress addressed other issues of European stability and international relations. These included:

• Naval Suppression of the Slave Trade: The powers discussed measures to suppress the Atlantic slave trade, though differences in national interests and maritime rights prevented concrete agreement on international naval patrols.
• Mediation between Sweden and Denmark: The Congress mediated a dispute between Sweden and Denmark related to territorial claims and financial compensation following the Napoleonic Wars.
• Status of the Grand Duchy of Baden: The Congress addressed issues related to the succession and sovereignty of the Grand Duchy of Baden.
• The issue of Spanish colonies in South America: While not a primary agenda item, the issue of Spain's increasingly unstable colonies in South America was raised, though no formal action was taken due to conflicting British and continental interests.

The Congress of Aix-la-Chapelle marked a significant moment in the post-Napoleonic order. It demonstrated the commitment of the Great Powers to maintaining peace and stability through diplomacy and cooperation. It also highlighted the growing tensions and competing interests within the Concert of Europe that would eventually contribute to its decline. The Congress is often cited as an example of early international cooperation and diplomacy in the 19th century.