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Further, the most important affairs, such as the concluding of peace, were withdrawn from the consuls, and they were in such matters obliged to have recourse to the senate and to act according to its instructions.