The Role of Custom

In the later republican era, custom (consuetudo) no longer operated as a direct source of law. However, it prevailed as a component in the formulation of the norms of positive law as found in statutory enactments, the edicts of the magistrates and the interpretations of the jurists.^[146] Thus, many forms of action devised by the praetors to address situations not covered by the existing ius civile reflected customary norms endorsed by public opinion and actually observed by the people (opinio necessitatis).^[147] As previously explained, the principal duty of the praetor when faced with a legal dispute was to determine whether the plaintiff’s claim was admissible and, in doing do, the magistrate was to a large extent guided by current public opinion and the general sentiment as to what was right and proper in the circumstances.

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