As long as the republic survived, the Twelve Tables formed the foundation of the Roman law, though they were interpreted and enlarged by such new enactments as the circumstances of the state demanded(298). Thus the _Lex Aquilia_ and _Alinia_ were mere modifications of different heads of the twelve tables. Most of the new laws were introduced in consequence of the increase of empire and luxury, and the conflicting interests of the various orders in the state. Laws, properly so called, were proposed by a superior magistrate, as the Consul, Dictator, or Prætor, with consent of the Senate; they were passed by the whole body of the people, patricians and plebeians, assembled in the Comitia Centuriata, and bore ever after the name of the proposer.
The _Plebiscita_ were enacted by the plebeians in the Comitia Tributa, apart from the patricians, and independently of the sanction of the Senate, at the _rogation_ of their own Tribunes, instead of one of the superior magistrates. The patricians generally resisted these decrees, as they were chiefly directed against the authority of the Senate, and the privileges of the higher orders of the state. But, by the _Lex Horatia_, the same weight and authority were given to them as to laws properly so termed, and thenceforth they differed only in name, and the manner in which they were enacted.
A _Senatusconsultum_ was an ordinance of the Senate on those points concerning which it possessed exclusive authority; but rather referred to matters of state, as the distribution of provinces, the application of public money, and the like, than to the ordinary administration of justice.