The Princeps, on the other hand, is not credited directly with any power of legislation; but the faculty for making _jus_, which was inherent in the _imperium_ of every Roman magistrate, and especially apparent in that of the praetor, was manifested by the Princeps in an unexampled degree. His methods of utterance are through the edict, the decree, and the rescript. The _edictum_ is, like that of the praetor, technically an interpretation of law; but the creative power associated with interpretation is here pushed to its extremest limits, and statute law supplemented this faculty inherent in the _imperium_ by explicitly declaring that whatever ordinances the Princeps might lay down should (with certain limitations fixed by precedents) be considered valid.[1810] Whether the edict of one Princeps bound his successor must have depended to some extent on the degree of formality in the utterance. Tiberius professes respect even for the _obiter dicta_ of Augustus;[1811] but this reverence was exaggerated, and none but the formal edicts expressed in written form could, as a rule, have been included in the _acta_. It is by no means certain that even these were always included in the _acta_ to which the oath was taken;[1812] but if an edict had been recognised as valid by several succeeding Principes and was then abandoned, some formal method of repudiation seems to have been necessary.[1813] The _decretum_ was, in its strict sense, the sentence of the Princeps when sitting as a high court of justice;[1814] as a _res judicata_ it necessarily possessed absolutely binding force for the case in which it was issued, and prevented any renewal of this process; but, unless formally rescinded in a succeeding reign, its validity as a precedent seems not to have been questioned, and the words _Caesar dixit_ appeal to the jurists almost with the force of law.[1815]