Proconsul (proconsul, meaning “acting on behalf of the consul”) was a Roman official who supported the consul (he had the so-called imperium maius) and was subordinate to it.
The consul was one of the most senior Roman officials elected by the centurial committee (comitia centuriata). In the Roman Republic, two consuls were elected for a given year, who had both civil-administrative and military power. Imperium militiae gave them the power to wage war; however, in the event of a protracted war and the imminent end of their term of office, the senate decided to extend the powers of the commander in order not to disturb operational activities. Thus, they received the title of proconsuls, formally reporting to the new consuls, but they could still command the Roman army and end the conflict in favour of Rome.
Originally, it was the duty of the proconsul to wage warfare according to the imperium militiae; with the growth of the Roman state, from the 2nd century BCE the proconsul also began to perform civil and administrative duties in the Roman provinces, becoming a kind of governor (apart from the provincial proconsul, praetors or proxies could manage). The proconsul outside the city of Rome had full consul powers and also had 12 lictors confirming his authority (imperium) and protecting him in places public.
The proconsul, like the consul, could apply for triumph. Returning from the war, the official went to Rome and reported on his achievements to the senate, which on this occasion gathered outside the sacred borders of Rome (pomerium), in the temple of Bellona or Apollo, located on the Field of Mars. The proconsul did not convene the senate in person, as did the consul, and on his behalf the praetor did. The Senate met outside pomerium, because the proconsul would lose imperium and the right to triumph upon crossing the border.
Civil wars in the 1st century BCE caused that outstanding personalities such as Sulla, Pompey and Caesar to begin to appear on the political scene in Rome. The deterioration of the political system and numerous bribes meant that more and more power began to accumulate in the hands of individuals. An example is the granting of a three-year proconsulate to Pompey in 67 BCE. or the later powers of Crassus and Caesar.
- imperial provinces – provinces whose nominal governor (in the rank of proconsul) on behalf of the senate and the Roman people was the emperor himself. In practice, the administration of the imperial provinces was exercised by legates freely appointed and dismissed by the emperor. These provinces were most often the borders of the Roman Empire, and legions under the direct authority of the emperor were stationed on them.
- Senate provinces – these provinces were owned by the Roman people and were far from Limes and therefore not endangered – therefore no legions were stationed there, which was to limit the possibility of the Senate taking power away from the emperor. Only Senate had the power to appoint governors (proconsuls).
The consuls’ power was de facto limited to Rome and the civil-administrative functions in the city. The proconsuls kept some competencies and we can talk about the formation of imperium proconsulare, which focused mainly on the civil-administrative role in the province.