§ 270. As the treaty-making Power is according to the Law of Nations in the hands of the head[502] of the State, it is he who is competent to conclude peace. But just as constitutional restrictions imposed upon heads of States regarding their general power of concluding treaties[503] are of importance for International Law, so constitutional restrictions imposed upon heads of States regarding their competence to make peace are of similar importance. And, therefore, such treaties of peace concluded by heads of States as violate constitutional restrictions are not binding upon the States concerned, because the heads have exceeded their powers. The Constitutions of the several States settle the matter differently, and it is not at all necessary that the power of declaring war and that of making peace should be vested by a Constitution in the same hands. In Great Britain the power of the Crown to declare war and to make peace is indeed unrestricted. But in the German Empire, for instance, it is different; for whereas the Emperor, the case of an attack on German territory excepted, may declare war only with the consent of the Bundesrath, his power of making peace is unrestricted.[504] [Footnote 502: See above, vol. I. § 495.] [Footnote 503: See above, vol. I. § 497.] [Footnote 504: See more examples in Rivier, II. p. 445.] The controverted question as to whether the head of a State who is a prisoner of war is competent to make peace ought to be answered in the negative. The reason is that the head of a constitutional State, although he does not by becoming a prisoner of war lose his position, he nevertheless thereby loses the power of exercising the rights connected with his position.[505] [Footnote 505: See Vattel, IV. § 13.] [Sidenote: Date of Peace.] § 271. Unless the treaty provides otherwise, peace commences with the signing of the peace treaty. Should the latter not be ratified, hostilities may be recommenced, and the unratified peace treaty is considered as an armistice. Sometimes, however, the peace treaty fixes a future date for the commencement of peace, stipulating that hostilities must cease on a certain future day. This is the case when war is waged in several or widely separated parts of the world, and when, therefore, it is impossible at once to inform the opposing forces of the conclusion of peace.[506] It may even occur that different dates are stipulated for the termination of hostilities in different parts of the world. [Footnote 506: The ending of the Russo-Japanese war was quite peculiar. Although the treaty of peace was signed on September 5, 1905, the agreement concerning an armistice pending ratification of the peace treaty was not signed until September 14, and hostilities went on till September 16.]