In ancient Rome, it was an unwritten rule that in the event of marriage the bride should bring a dowry (dos). The additional capital contributed to the husband was to facilitate the maintenance of the family (onera matrimonii) and the protection of the wife or children in the event of a breakdown of the relationship (divortium). Obviously, the larger the dowry the father of the bride could propose, the greater the chance that the husband would accept the woman’s hand.
It should be noted, however, that it was not unusual for a woman not to contribute a dowry (mulier indonata); but surely such a woman was suspicious and unwelcome as a candidate for a wife. For this reason, women from poor families had problems with getting married. Often, Roman citizens looked for potential wives in richer families, which guaranteed a high dowry.
The transfer of the dowry was confirmed during the marriage. There was either a dowry from the father (dos profectitia) or a dowry from a person other than the father (dos adventitiado). Moreover, the dowry was established once for a specific marriage.
Interestingly, in the middle of the 5th century CE, under Emperor Majorian, a legal obligation was introduced, requiring a woman to bring a dowry with her to marriage; failure to do so could bring infamy to the couple and prevent the children from being recognized by the state as lawfully born of the union. Such a law appears to have been quickly withdrawn.