It may be maintained that the establishment of Greece and Belgium inferred the breakdown of the Holy Alliance. But it was not till the year 1848 that this alliance was totally swept away through the disappearance of absolutism and the victory of the constitutional system in most States of Europe. Shortly afterwards, in 1852, Napoleon III., who adopted the principle of nationality,[45] became Emperor of France. Since he exercised preponderant influence in Europe, one may say that this principle of nationality superseded in European politics the principle of legitimacy.
[Footnote 45: See Bulmerincq, "Praxis, Theorie und Codification des Völkerrechts" (1874), pp. 53-70.]
The last event of this period is the Crimean War, which led to the Peace as well as to the Declaration of Paris in 1856. This war broke out in 1853 between Russia and Turkey. In 1854, England, France, and Sardinia joined Turkey, but the war continued nevertheless for another two years. Finally, however, Russia was defeated, a Congress assembled at Paris, where England, France, Austria, Russia, Sardinia, Turkey, and eventually Prussia, were represented, and peace was concluded in March 1856. In the Peace Treaty, Turkey is expressly received as a member into the Family of Nations. Of greater importance, however, is the celebrated Declaration of Paris regarding maritime International Law which was signed on April 16, 1856, by the delegates of the Powers that had taken part in the Congress. This declaration abolished privateering, recognised the rules that enemy goods on neutral vessels and that neutral goods on enemy vessels cannot be confiscated, and stipulated that a blockade in order to be binding must be effective. Together with the fact that at the end of the first quarter of the nineteenth century the principle of the freedom of the high seas[46] became universally recognised, the Declaration of Paris is a prominent landmark in the progress of the Law of Nations. The Powers that had not been represented at the Congress of Paris were invited to sign the Declaration afterwards, and the majority of the members of the Family of Nations did sign it before the end of the year 1856. The few States, such as the United States of America, Spain, Mexico, and others, which did not then sign,[47] have in practice since 1856 not acted in opposition to the Declaration, and one may therefore, perhaps, maintain that the Declaration of Paris has already become or will soon become universal International Law through custom. Spain and Mexico, however, signed the Declaration in 1907, as Japan had already done in 1886.