This statement is quoted from the second edition of the Cambridge Ancient History and seems to be fully correct. Nevertheless there is an “argument” that has not attracted particular attention so far: at least one ancient source denies that “such a dual magistracy was established immediately after the overthrow of the monarchy.” This source is Cassius Dio's Roman History. Dio's reconstruction of the origin of the consulship is rather different from the traditional one and seems to be, at its core, more ancient as well. Before coming to the point, in order to better appreciate the value of this unconventional tale, it is worth dwelling briefly on the circle of Severan jurists whom Dio knew well, on Dio's attention to the pre-Livian tradition and on his interest in the history of Roman institutions.

Preliminary remarks

A distinguishing characteristic of Cassius Dio's Roman History is its strong interest in the history of Roman institutions and magistracies, already pointed out in the early twentieth century by Cary (“he excels the other historians of Rome in the attention paid to constitutional and administrative matters”) and Vrind. De Sanctis passed similar judgment, though adding a negative comment on Dio's reliability as a whole: “Superiore d'assai per intelligenza pratica delle cose politiche e per cognizione dell'organismo dello Stato romano a Livio e a Dionisio, i suoi tentativi però non approdarono che ad alterare ancora la tradizione già sì alterata che era pervenuta fino a lui.” Hinard has recently come back to the topic: “On n'a pas assez remarqué que Dion prêtait une attention particulière aux questions institutionnelles et que c'est probablement dans ce domaine qu'il est le plus utile;” sometimes “c'est Dion qui donne les indications les plus précises, les autres sources ne servant qu’à recouper ces informations.” At the same time the severe opinion that made Cassius Dio “le plus prodigue en renseignements, vulnérable aux critiques” has given way to more cautious judgments (“if the work is not a masterpiece, its author deserves attention and respect”) and even to real eulogies: “In using his Roman history…we tend to slight or pass by the solid contributions he often makes to our knowledge. Greater alertness to his virtues as an historian, to the valuable, sometimes unique interpretations and data he provides is needed to achieve a more balanced perception of Cassius Dio's work;” “Dion est bien un historien qui n’était pas dépourvu de talent et qu'on aurait tort de négliger parce qu'il avait une immense culture et qu'il a travaillé avec intelligence et une indiscutable compétence, du moins pour la période républicaine.”