The Rhine crisis broke out in Europe in the summer of 1840, as a result of a diplomatic split between France and other powers (Austria, Russia, Prussia and Great Britain). The reason was a different opinion on the settlement of the dispute within the Ottoman Empire. As France felt isolated in this, it began to threaten with a war in Europe and arm ardently. Metternich, who stayed in Kynžvart in August together with other diplomats (in particular Lord Beauvale, British Ambassador, Count Ficquelmont, Austrian Ambassador to Russia, Count Maltzan, Prussian ambassador, then the representative of France, other Austrian diplomats and Papal nuncio) at an informal diplomatic conference, considered the situation to be serious, and therefore prepared the Peace League Proposal, whose member states should in the future accept the commitment to resolve disputes by peaceful means or to defend an invaded state by force. The Peace League proposal consisted of six articles that clearly described how to prevent war and how to restore peace if the war had already broken out. Metternich's proposal reminds us remarkably of the content of the founding North Atlantic Treaty of 1949. However League´s proposal was rejected by the government in London (where was dispatched from Kynžvart Chateau) and therefore hasn´t been discussed anymore.

(Source: Miroslav Šedivý, Metternich, the Great Powers and the Eastern Question, Pilsen 2013, pp. 807-810) download: www.metternich.zcu.cz.

Most recently, the topic has been elaborated in a historical analytical study Metternich's League to Preserve Peace and the Conservative Elites’ Doubts about the Functionality of the Post-Napoleonic Order IN: Austrian History Yearbook, Cambridge University Press, 2023, pp. 1 - 16.