Cicero enumerates seven forms of law. Three of these are not heard of thereafter in Roman juristic writing. Evidently already in Cicero's time they belonged to the past and had ceased to be effective forms of the actual law. The four remaining, namely, statutes, resolutions of the senate, edicts of the magistrates, and the authority of those learned in the law, come to three--legislation, administrative edicts, and juristic reasoning on the basis of the legal tradition. And these correspond to the three elements which made up the law. First, there was the _ius ciuile_: the Twelve Tables, subsequent legislation, interpretation of both, and the traditional law of the city. Second, there was the mass of rules, in form largely procedural, which was contained in the edicts. The growing point of the law had been here and to some extent growth was still going on through this means. Indeed this part of the law reached its final form under Hadrian. Third, there were the writings of the jurisconsults. The growing point of the law had begun to be here and this was the most important form of law in the classical period from Augustus to the third century. This part of the law got its final form in the Digest of Justinian. Of the three elements, the first was thought of originally as declared and published custom. Later it was thought of as resting on the authority of the state. It was obviously local and peculiar to Rome. In form it rested on the legislative power of the Roman people, supplemented by a mere interpretation of the legislative command with only the authority of customary acceptance. In Greek phrase it rested on convention and enactment. The second purported to be the rules observed by civilized peoples, and on points of commercial law may well have been an approximation thereto. Apart from this, however, according to ancient ideas of personal law, the rules which obtained among civilized peoples were eminently a proper law to apply between citizen and non-citizen. In Greek phrase it was law by convention. The basis of the third was simply reason. The jurisconsult had no legislative power and no _imperium_. The authority of his _responsum_, as soon as law ceased to be a class tradition, was to be found in its intrinsic reasonableness; in the appeal which it made to the reason and sense of justice of the _iudex_. In Greek phrase, if it was law, it was law by nature.