The rapid development of this doctrine of intervention in the seven years immediately following the second fall of Napoleon not only seriously menaced the liberties of Europe, but also threatened to control the destiny of the new world. At the Congress of Vienna Austria, France, Great Britain, Prussia, and Russia had formed a close union and had signed the treaty upon which the peace of Europe rested for the next half century. The agreement made at Vienna was reaffirmed with some minor changes, after the second overthrow of Napoleon, at Paris, November 20, 1815. France was now practically excluded from the alliance. This treaty undertook especially to guard against any further disturbance of the peace of Europe by Napoleon or France. One of the most significant features of the treaty, or what was to prove so, was the agreement definitely laid down in the sixth article, providing for meetings of the powers at fixed periods. The first conference held in accordance with this understanding was that at Aix-la-Chapelle in October, 1818. France was readmitted as a member of the alliance and her territory evacuated by the allied armies. The quintuple alliance thus formed declared that it had no other object than the maintenance of peace; that the repose of the world was its motive and its end. The language of the declaration had been in a large measure neutralized to suit the views of the British government. Lord Liverpool had said to Castlereagh before the meeting of the conference: "The Russian must be made to feel that we have a parliament and a public, to which we are responsible, and that we cannot permit ourselves to be drawn into views of policy which are wholly incompatible with the spirit of our government." The members of the British cabinet, except Canning, did not object seriously to the system of congresses at fixed intervals, but to the declarations publicly set forth by them. Canning, on the other hand, objected to the declarations and to the conferences themselves, "meetings for the government of the world," as he somewhat contemptuously termed them. It had been generally supposed that the question of the Spanish colonies would come up for discussion at Aix-la-Chapelle. Castlereagh assured the United States, through Bagot, the British minister at Washington, that while England would act with the allied powers at Aix-la-Chapelle in mediation between Spain and her colonies, her mediation would be limited entirely to the employment of her influence and good offices and that she would not take any measures that might assume a character of force.[49]