the functions of the three supreme magistrates, and assigned administration and the conduct of war to the two first, and the management of justice to the third.  But the change did not stop here.  The consuls, although they were in law wholly and everywhere co-ordinate, naturally from the earliest times divided between them in practice the different departments of duty (-provinciae-).  Originally this was done simply by mutual concert, or in default of it by casting lots; but by degrees the other constituent authorities in the commonwealth interfered with this practical definition of functions.  It became usual for the senate to define annually the spheres of duty; and, while it did not directly distribute them among the co-ordinate magistrates, it exercised decided influence on the personal distribution by advice and request.  In an extreme case the senate doubtless obtained a decree of the community, definitively to settle the question of distribution;(15) the government, however, very seldom employed this dangerous expedient.  Further, the most important affairs, such as the concluding of peace, were withdrawn from the consuls, and they were in such matters obliged to have recourse to the senate and to act according to its instructions.  Lastly, in cases of extremity the senate could at any time suspend the consuls from office; for, according to an usage never established by law but never violated in practice, the creation of a dictatorship depended simply upon the resolution of the senate, and the fixing of the person to be nominated, although constitutionally vested in the nominating consul, really under ordinary circumstances lay with the senate.

Limitation of the Dictatorship

The old unity and plenary legal power of the -imperium- were retained longer in the case of the dictatorship than in that of the consulship.  Although of course as an extraordinary magistracy it had in reality from the first its special functions, it had in law far less of a special character than the consulate.  But it also was gradually affected by the new idea of definite powers and functions introduced into the legal life of Rome.  In 391 we first meet with a dictator expressly nominated from theological scruples for the mere accomplishment of a religious ceremony; and though that dictator himself, doubtless in formal accordance with the constitution, treated the restriction of his powers as null and took the command of the army in spite of it, such an opposition on the part of the magistrate was not repeated on occasion of the subsequent similarly restricted nominations, which occurred in 403 and thenceforward very frequently.  On the contrary, the dictators thenceforth accounted themselves bound by their powers as specially defined.

Restriction as to the Accumulation and the Reoccupation of Offices