This articles examines Henry Maine’s arguments about the prospects of achieving a lasting and comprehensive peace. In a series of lectures on International Law, Maine famously held that ‘war is as old as mankind but peace is a modern invention’. The sentence situates Maine within a long-standing debate on the state of nature. The article reconstructs the meaning of the sentence by interpreting it in light of Maine’s broader theoretical framework and comparative-historical approach. An important conclusion of the article is that Maine never meant the sentence to express a gullible evolutionist perspective on the problem of war and peace. The invention of peace would not, Maine understood, solve the problem of war. Another important finding concerns the centrality of historical arguments to the debate on the state of nature. Proper historical consideration, the article concludes, does not resolve the problem of the state of nature, but dissolves it.