Law on the Acquisition and Loss of Confederative and State Citizenship (June 1, 1870)*
§ 1. Citizenship in the Confederation is acquired through citizenship in a federal state and expires with the loss of the latter.
[ . . . ]
§ 2. In the future, citizenship in a federal state will be established only on the basis of the following:
1) descent (§ 3),
2) legitimation (§ 4),
3) marriage (§ 5),
4) admission, for a North German and (§§ 6 ff.).
5) naturalization, for a foreigner (§§ 6 ff.).
Adoption alone does not have this effect.
§ 3. Through birth, even when it occurs abroad, legitimate children of a North German man acquire the citizenship of the father, illegitimate children of a North German woman acquire the citizenship of the mother.
§ 4. If the father of an illegitimate child is a North German and the mother does not have the same citizenship as the father, the child acquires, through legitimation effected in accordance with legal regulations, the citizenship of the father.
§ 5. Marriage to a North German confers the citizenship of the husband upon the wife.
§ 6. Admission, as well as naturalization (§ 2 No. 4 and 5), takes effect through the issuance of a certificate by a senior administrative authority.
* Wherever the term “North German” appears in the law of 1870, the term “German” appears in the law after 1871. (All footnotes adapted from Ernst Rudolf Huber, ed., Dokumente zur Deutschen Verfassungsgeschichte [Documents on German Constitutional History], 3rd rev. ed., vol. 2, 1851-1900. Stuttgart: Kohlhammer, 1986, p. 313-17.)