Roman law, like that of other nations, of course originated in custom, but the part played by custom as a source of law in historical times is comparatively small.
For the Romans law was primarily statute law, as is shown by their tendency to ascribe all ancient rules to laws enacted by one or other of the kings, and the basic law of Rome, the XII Tables, was, in fact, statutory. Nevertheless, custom was responsible for the introduction of some rules –Gaius, for instance, tells us that the legis actio per pignoris capionem was used for the enforcement of some claims in accordance with statute, in others by custom, and Cicero enumerated mos among the sources of law. But the republic had no definite theory in the matter, and the discussion of imperial views must be postponed.
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- Sources of law in the republic
+ Lex and plebiscitum
+ Interpretatio
+ Edicta magistratuum
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Source:
Historical introduction to the study of Roman law, H. F. Jolowicz, page 99.
