Whenever a case arises in which a State lacking the legal qualification to make war nevertheless actually makes war, such State is a belligerent, the contention is real war and all the rules of International Law respecting warfare apply to it.[111] Therefore, an armed contention between the suzerain and the vassal, between a full-Sovereign State and a vassal State under the suzerainty of another State, and, lastly, between a Federal State and one or more of its members, is war[112] in the technical sense of the term according to the Law of Nations. [Footnote 111: This is quite apparent through the fact that Bulgaria by accession became a party to the Geneva Convention at a time when she was still a vassal State under Turkish suzerainty.] [Footnote 112: See above, § 56, and Baty, _International Law in South Africa_ (1900), pp. 66-68.] [Sidenote: Insurgents as a Belligerent Power.] § 76. The distinction between legal qualification and actual power to make war explains the fact that insurgents may become a belligerent Power. It is a customary rule of the Law of Nations that any State may recognise insurgents as a belligerent Power, provided (1) they are in possession of a certain part of the territory of the legitimate Government; (2) they have set up a Government of their own; and (3) they conduct their armed contention with the legitimate Government according to the laws and usages of war.[113] Such insurgents in fact, although not in law, form a State-like community, and practically they are making war, although their contention is by International Law not considered as war in the technical sense of the term as long as they have not received recognition as a belligerent Power. [Footnote 113: See above, § 59. See also Rougier, _Les guerres civiles_, &c. (1903), pp. 372-447, and Westlake, I. pp. 50-57. The Institute of International Law, at its meeting at Neuchatel in 1900, adopted a body of nine articles concerning the rights and duties of foreign States in case of an insurrection; articles 4-9 deal with the recognition of the belligerency of insurgents. See _Annuaire_, XVIII. p. 227.] [Sidenote: Principal and accessory Belligerent Parties.] § 77. War occurs usually between two States, one belligerent party being on each side. But there are cases in which there are on one or on both sides several parties, and in some of such cases principal and accessory belligerent parties are to be distinguished.