3. That both man and woman should be unmarried. Polygamy was never practiced at Rome.
§68. 4. That the parties should not be nearly related. The restrictions in this direction were fixed rather by public opinion than by law and varied greatly at different times, becoming gradually less severe. In general it may be said that marriage was absolutely forbidden between ascendants and descendants, between other cognates within the fourth degree (§25), and the nearer _adfines_ (§26). If the parties could satisfy these conditions they might be legally married, but distinctions were still made that affected the civil status of the children, although no doubt was cast upon their legitimacy or upon the moral character of their parents.
§69. If the husband and wife were both Roman citizens, their marriage was called _iustae nuptiae_, which we may translate "regular marriage," their children were _iusti liberi_ and were by birth _cives optimo iure_, "possessed of all civil rights."
If but one of the parties was a Roman citizen and the other a member of a community having the _ius conubii_ but not the full _civitas_, the marriage was still called _iustae nuptiae_, but the children took the civil standing of the father. This means that if the father was a citizen and the mother a foreigner, the children were citizens; but if the father was a foreigner and the mother a citizen, the children were foreigners (_peregrini_) with the father.
But if either of the parties was without the _ius conubii_, the marriage, though still legal, was called _nuptiae iniustae_ or _matrimonium iniustum_, "an irregular marriage," and the children, though legitimate, took the civil position of the parent of lower degree. We seem to have something analogous to this in the loss of social standing which usually follows the marriage of a person with one of distinctly inferior position.
§70. Betrothals.--Betrothal (_sponsalia_) as a preliminary to marriage was considered good form but was not legally necessary and carried with it no obligations that could be enforced by law. In the _sponsalia_ the maiden was promised to the man as his bride with "words of style," that is, in solemn form. The promise was made, not by the maiden herself, but by her _pater familias_, or by her _tutor_ if she was not _in potestate_. In the same way, the promise was made to the man directly only in case he was _sui iuris_, otherwise to the Head of his House, who had asked for him the maiden in marriage. The "words of style" were probably something like this: