A peace congress, in international relations, has at times been defined in a way that would distinguish it from a peace conference (usually defined as a diplomatic meeting to decide on a peace treaty), as an ambitious forum to carry out dispute resolution in international affairs, and prevent wars. This idea was widely promoted during the nineteenth century, anticipating the international bodies that would be set up in the twentieth century with comparable aims.

The genesis of the idea of a meeting of representatives of different nations to obtain by peaceful arbitrament a settlement of differences has been traced to the year 1623 in modern history, to a French monk, Émeric Crucé, who wrote a work entitled "The New Cyneas", a discourse showing the opportunities and the means for establishing a general peace and liberty of conscience to all the world and addressed to the monarch and the sovereign princes of the time. He proposed that a city, preferably Venice, should be selected where all the powers had ambassadors and that there should be a universal union, including all peoples. He suggested careful arrangement as to priority, giving the first place to the pope.