In ancient Rome, a promagistrate (Latin: pro magistratu) was a person who was granted the power via prorogation to act in place of an ordinary magistrate in the field. This was normally pro consule or pro praetore, that is, in place of a consul or praetor, respectively. This was an expedient development, starting in 327 BC and becoming regular by 241 BC, that was meant to allow consuls and praetors to continue their activities in the field without disruption.

Prorogation created an official with no civilian authority or responsibility in Rome and allowed commanders to retain their position indefinitely, weakening the time-limited check that Romans had over their commanders.[1] Prorogation, by allowing veteran commanders to stay rather than being rotated out for someone with little experience, also helped increase the chances of victory. In the late Republic, politics, often motivated by the ambitions of individuals, decided whose commands were extended.[2]

Sometimes men who held no elected public office – that is, private citizens (privati) – were given imperium and prorogued, as justified by perceived military emergencies. In the late republic, this was most exemplified by Pompey, who held a series of promagisterial commands before ever holding a magistracy or even joining the senate. With the acquisition of provinces outside of Italy and the expansion of the quaestiones perpetuae (permanent courts), it became normal for the provincial governors to be promagistrates. By the late republic, practically all governors were dispatched pro consule, regardless of their last urban magistracy.

The titles "proconsul" and "propraetor" are not used by Livy or literary sources of the republican era. Those Romans did not view a promagistracy a formal office in the republic but rather as an administrative expedient.[3]

  1. ^ Drogula 2015, p. 212.
  2. ^ Pittenger 2009, p. 77.
  3. ^ Brennan 2001, p. 603, noting "the Romans obviously never came to terms with recognising the promagistracy as an actual office" after explaining that neither Livy nor Cicero use the titles "proconsul" or "propraetor".