There were three Treaties of Aix-la-Chapelle. Although "Aix-la-Chapelle", the French name of the German city of Aachen, is an exonym now rarely used in English, the name Treaty of Aachen is rarely used.
There were three Treaties of Aix-la-Chapelle. Although "Aix-la-Chapelle", the French name of the German city of Aachen, is an exonym now rarely used in English, the name Treaty of Aachen is rarely used.