Concert of Europe, term used in the 19th cent. to designate a loose agreement by the major European powers to act together on European questions of common interest. The concert emerged after the Congress of Vienna (1814-15) and included the Quadruple Alliance powers of Great Britain, Austria, Prussia, and Russia, and, as of 1818, France as well. It aimed to preserve peace by concerted diplomatic action reinforced by periodic conferences dealing with problems of mutual concern.