The Concert of Europe: The Holy Alliance, the Congress System, and Its Limits

To enforce the Vienna settlement, the great powers built two overlapping structures. The Holy Alliance, signed in September 1815 at Tsar Alexander I's initiative by Russia, Austria, and Prussia, committed its monarchs in vaguely religious terms to govern according to Christian principles; Britain, through Castlereagh, refused to sign it, citing constitutional limits on committing the government without parliamentary approval. The far more concrete Quadruple Alliance, signed the same November between Austria, Russia, Prussia, and Britain, bound its members to uphold the Vienna settlement and, under its Article VI, to meet periodically in congresses to consult on shared European interests, the direct seed of what became known as the Concert of Europe. France formally joined this system at the Congress of Aix-la-Chapelle in 1818, turning it into the Quintuple Alliance.