Nationality in relation to the succession of States of time.78 What constitutes a “reasonable” time limit may depend upon the circumstances of the succession of States, but also on the categories to which persons concerned entitled to the right of option belong. In the view of the Commission, a “reasonable time limit” is a time limit necessary to ensure an effective exercise of the right of option. Article 12. Unity of a family Where the acquisition or loss of nationality in relation to the succession of States would impair the unity of a family, States concerned shall take all appropriate measures to allow that family to remain together or to be reunited. Commentary (1) There are a number of examples from State practice of provisions addressing the problem of the common destiny of families upon a succession of States. The general policy in the treaties concluded after the First World War was to ensure that the members of a family acquired the same nationality as the head of the family, whether the latter had acquired it automatically or upon option.79 Article 19 of the Treaty of Peace with Italy, of 1947, on the contrary, did not envisage the simultaneous acquisition by a wife of her husband’s nationality following his exercise of an option. Minor children, however, automatically acquired the nationality for which the head of the family had opted.80 (2) The principle of family unity was also highlighted, albeit in a broader context, in the comment to article 19 of the Draft Convention on Nationality prepared by Harvard Law School, where it was stated that “[i]t is desirable in some measure that members of a family should have the same nationality, and the principle of family unity is regarded in many countries as a sufficient basis for the application of this simple solution”.81 (3) The approach usually followed during the process of decolonization was to enable a wife to acquire the 78 See Exchange of letters and declarations adopted on 19 March 1962 at the close of the Evian talks, constituting an agreement (Paris and Rocher Noir, 3 July 1962), United Nations, Treaty Series, vol. 507, p. 25, at pp. 35 and 37. 79 See the provisions cited in footnote 62 above. 80 Materials on Succession of States . . . (footnote 37 above), p. 59. 81 Research in International Law . . . (footnote 19 above), p. 69. The main deficiency of provisions envisaging the simultaneous change of nationality of all the members of a family following the change of the nationality of the head of the family was the fact that they were placing the woman in a position of subordination. In an attempt to overcome this problem, article 4 of the resolution adopted by the Institute of International Law on 29 September 1896 stipulated that, “[u]nless the contrary has been expressly reserved at the time of naturalization, the change of nationality of the father of a family carries with it that of his wife, if not separated from her, and of his minor children, saving the right of the wife to recover her former nationality by a simple declaration, and saving also the right of option of the children for their former nationality, either in the year following their majority, or beginning with their emancipation, with the consent of their legal assistant” (cited in ibid., p. 75). 35 nationality of her husband upon application, as evidenced by relevant legal instruments of Barbados, Botswana, Burma, Guyana, Jamaica, Malawi, Mauritius, Sierra Leone and Trinidad and Tobago,82 or by various treaty provisions, such as annex D to the Treaty concerning the Establishment of the Republic of Cyprus of 16 August 196083 and article 6 of the Treaty of Cession of the French Establishments of Pondicherry, Karikal, Mahe and Yanam, between India and France, signed at New Delhi on 28 May 1956.84 (4) A concern for the preservation of the unity of the family is also apparent in some national legislations of successor States that emerged from the recent dissolutions in Eastern and Central Europe.85 (5) The Commission is of the view that the thrust of article 12 is closely connected to nationality issues in relation to the succession of States, as the problem of family unity may arise in such a context on a large scale. It also concludes that, while it is highly desirable to enable members of a family to acquire the same nationality upon a succession of States, it is not necessary to formulate a strict rule to this end, as long as the acquisition of different nationalities by the members of a family did not prevent them from remaining together or being reunited. Accordingly, the obligation set out in article 12 is of a general nature. For example, whenever a family faces difficulties in living together as a unit as a result of provisions of nationality laws relating to a succession of States, States concerned are under an obligation to eliminate such legislative obstacles. The expression “appropriate measures”, however, is intended to exclude unreasonable demands of persons concerned in this respect. (6) Concerning possible different interpretations of the concept of “family” in various regions of the world, the Commission is of the view that a succession of States usually involves States from the same region sharing the same or a similar interpretation of this concept, so that the said problem would not arise with frequency. Article 13. Child born after the succession of States A child of a person concerned, born after the date of the succession of States, who has not acquired any nationality, has the right to the nationality of the State concerned on whose territory that child was born. Commentary (1) Article 13 deals with the problem of children born to persons concerned after the date of the succession of States. It follows from its title that the present topic is limited to questions of nationality solely in relation to the 82 Materials on Succession of States . . . (footnote 37 above), pp. 124-125, 137-138, 145-146, 203-204, 246, 307-308, 353-354, 389390, and 429 respectively. 83 Ibid., pp. 172-178. 84 Ibid., p. 87. 85 For relevant examples, see paragraphs (20) and (21) of the commentary to draft article 9 proposed by the Special Rapporteur in his third report (footnote 10 above).