the Congress of Vienna (1815): Ambassadors, legates and nuncios were personal representatives of their sovereign. Envoys and ministers represented their government and were accredited to the receiving sovereign. Ministers resident formed an intermediate class between ministers and chargés. This rank was created by the Congress of Aix-la-Chapelle (1818) Chargés d'affaires were accredited by their foreign minister to the receiving foreign minister. The rank of envoy was short for "envoy extraordinary and minister plenipotentiary", and was more commonly known as "minister". For example, the "envoy extraordinary and minister plenipotentiary of the United States to the French Empire" was known as the "United States Minister to France" and addressed as "Monsieur le Ministre". An Ambassador was regarded as the personal representative of his sovereign as well as his government. Only major monarchies would exchange Ambassadors with each other, while smaller monarchies and republics only sent Ministers. Because of diplomatic reciprocity, Great Powers would only send a minister to a smaller monarchy or a republic. For example, in the waning years of the Second French Empire, the United Kingdom sent an ambassador to Paris, while Sweden-Norway and the United States sent ministers. The rule that only monarchies could send ambassadors was more honored in the breach than the observance. This had been true even before the Congress of Vienna, as England continued to appoint ambassadors after becoming a republic in 1649. Countries that overthrew their monarchs proved to be unwilling to accept the lower rank accorded to a republic. After the Franco-Prussian War, the French Third Republic continued to send and receive ambassadors. The rule became increasingly untenable as the United States grew into a Great Power. The United States followed the French precedent in 1893, and began to exchange ambassadors with other Great Powers. Historically, the order of precedence had been a matter of great dispute. European powers agreed that the papal nuncio and imperial ambassador would have precedence, but could not agree on the relative precedence of the kingdoms and smaller countries. In 1768, the French and Russian ambassadors to Great Britain even fought a duel over who had the right to sit next to the imperial ambassador at a court ball. After several diplomatic incidents between their ambassadors, France and Spain agreed in 1761 to let the date of arrival determine their precedence. In 1760, Portugal attempted to apply seniority to all ambassadors, but the rule was rejected by the