In the year 309 it was enacted by the Canuleian plebiscite, that a marriage between a patrician and a plebeian should be valid as a true Roman marriage, and that the children begotten of such a marriage should follow the rank of the father.

At the same time it was further carried that, in place of consuls, military tribunes--of these there were at that time, before the division of the army into legions, six, and the number of these magistrates was adjusted accordingly-with consular powers( 1) and consular duration of office should be elected by the centuries.
The proximate cause was of a military nature, as the various wars required a greater number of generals in chief command than the consular constitution allowed; but the change came to be of essential importance for the conflicts of the orders, and it may be that that military object was rather the pretext than the reason for this arrangement.

According to the ancient law every burgess or -- metoikos-- liable to service might attain the post of an officer,( 2) and in virtue of that principle the supreme magistracy, after having been temporarily opened up to the plebeians in the decemvirate, was now after a more comprehensive fashion rendered equally accessible to all freeborn burgesses.

The question naturally occurs, what interest the aristocracy could have--now that it was under the necessity of abandoning its exclusive possession of the supreme magistracy and of yielding in the matter--in refusing to the plebeians the title, and conceding to them the consulate under this singular form ?( 3) But, in the first place, there were associated with the holding of the supreme magistracy various honorary rights, partly personal, partly hereditary; thus the honour of a triumph was regarded as legally dependent on the occupancy of the supreme magistracy, and was never given to an officer who had not administered the latter office in person; and the descendants of a curule magistrate were at liberty to set up the image of such an ancestor in the family hall and to exhibit it in public on fitting occasions, while this was not allowed in the case of other ancestors.( 4) It is as easy to be explained as it is difficult to be vindicated, that the governing aristocratic order should have allowed the government itself to be wrested from their hands far sooner than the honorary rights associated with it, especially such as were hereditary; and therefore, when it was obliged to share the former with the plebeians, it gave to the actual supreme magistrate the legal standing not of the holder of a curule chair, but of a simple staff-officer, whose distinction was one purely personal.
Of greater political importance, however, than the refusal of the -ius imaginum- and of the honour of a triumph was the circumstance, that the exclusion of the plebeians sitting in the senate from debate necessarily ceased in respect to those of their number who, as designated or former consuls, ranked among the senators whose opinion had to be asked before the rest; so far it was certainly of great importance for the nobility to admit the plebeian only to a consular office, and not to the consulate itself.
Opposition of the Patriciate But notwithstanding these vexatious disabilities the privileges of the clans, so far as they had a political value, were legally superseded by the new institution; and, had the Roman nobility been worthy of its name, it must now have given up the struggle.

But it did not.