Congress of Vienna

Opened in September 1814, the congress gathered sovereigns and two hundred delegations in Vienna, in a whirl of balls of which the Prince de Ligne said that it "dances but does not walk". Decisions were in fact taken between four powers: Metternich's Austria, Alexander's Russia, Hardenberg's Prussia and Castlereagh's Britain.

Representing a defeated country and excluded from the directory of four, Talleyrand imposed the principle of legitimacy — thrones belong to dynasties, not to conquerors — which gave France a moral voice. The quarrel over Saxony and Poland did the rest: on 3 January 1815 he signed a secret alliance with London and Vienna directed against Russia and Prussia. France was once again a power of the concert.

The guiding principle was balance and the containment of France: a Kingdom of the Netherlands to the north, Prussia installed in the Rhineland, Piedmont enlarged by Genoa, Switzerland neutralised. Germany became a Confederation of thirty-nine states presided over by Austria; Lombardy-Venetia returned to Vienna; Poland became a kingdom tied to the tsar.

The Final Act was signed on 9 June 1815, nine days before Waterloo — whose outcome changed none of its clauses. This system, completed by the Holy Alliance, held until the revolutions of 1848 and, in essence, until 1914: there would be no general war in Europe for ninety-nine years.