Lucius Flavius Aper Aper ( full name Lucius Flavius Aper , date of birth unknown ) was a Roman soldier and public servant in the second half of the Third Century AD who rose to the highest office in the Imperial Service only to fall in the most spectacular fashion . His career coincided with and benefited from the momentous changes in the structure of the Roman army and the Roman state introduced by the Emperor Gallienus and his successors that brought equestrian officials with military backgrounds ( such as Aper ) to the fore in the government of the Empire . Obviously a man of considerable ability , he nevertheless owed his final success to patronage and influence - in his case to the relationship he achieved with the current Imperial Family . Similarly his fall was a consequence of bad luck and bad judgement which brought him into fatal conflict with the future Emperor Diocletian . Background . Nothing is known of Aper ' s origins or the date and circumstances of his birth . Career . Early appointments . Aper is identified with the Aper described as " vir Egregius praepositus legionum V Macedonicae atque XIII Geminae " on an epigraph dated @ 267 - 8 AD , found at " Poetovio " in the province of " Pannonia Superior " ( now Ptuj in Slovenia ) , a fortress in the eastern Julian Alps where he was , presumably , in command of the garrison . This text indicates that Aper was a " Vir Egregius " ( i . e . ' Outstanding Man ' , the lowest grade of the equestrian order ) and a " Praepositus " ( I . e . a ' man put in charge ' of a detached force charged with a specific mission ) . His command consisted of comprised elements ( " vexillationes " ) of " Legio V Macedonica " and " Legio XIII Gemina " - there is no known instance of a " praepositus " commanding a full legion . The need for these " ad hoc " commands was a reflection of the prevailing uncertainty caused by barbarian incursions and domestic unrest - especially in the " Pannonia " provinces through which ran the great roads from the frontier to Italy - and the inability of the army to cope with the situation when deployed essentially for pre - emptive defence of the frontiers . This brought about a great expansion of the command - opportunities for equestrian officers , normally professional soldiers who had achieved equestrian status by rising through the ranks of the legionary centurionate . The same Aper appears on an undated epigraph from " Aquincum " in " Pannonia Inferior " ( Budapest , Hungary on which he is shown as " Vir Egregius agens vices praesidis " . This indicates that he was still a third grade equestrian official , but was now acting governor of the province . At this time " Pannonia Inferior " was still a praetorian province ( i . e . normally requiring a senatorial governor , a " legatus pro praetore " , which suggests that the terminology " agens vices praesidis " i . e . ' acting in lieu of the ( unappointed ) governor ' ) was a formula devised to give Aper ' s appointment legal force . " Pannonia Inferior " ' s status as a praetorian province was not to change for some years after Aper ' s appointment . Another epigraph records that there was a governor of senatorial status , probably shortly before 283 AD - i . e . after Aper ' s term in this post for by 283 Aper was " Praetorian Prefect " - see below . There is no way of knowing the specific circumstances that had led the Imperial Authorities to give Aper this posting , but the most likely reason was that the local situation required a man with military experience and that no suitable senatorial could be found . As in the case of Aper ' s earlier appointment in " Poetovio " , the prevailing disorder meant that this was a problem that increasingly confronted the Imperial government at this time and that , increasingly , the solution was to appoint an equestrian officer " pro temp . " . By 283 it had been possible to find a senator able / willing to do the job in " Pannonia Inferior " . However , the problem of finding suitable senators to govern provinces was still endemic and under Diocletian the process of equestrianising this function was carried to its logical conclusion and knights , usually professional soldiers , gradually replaced senators as governors of the provinces previously reserved by law for senators . Apogee and downfall . At the outset of the reign of the Emperor Numerian ( 284 AD ) a man named Aper was already " en poste " as Praetorian Prefect . The " Vita Cari " also says that he was the father of Numerian ' s wife . It is probable that this Aper was the same man as the one already noted as " praepositus " of a detached force and as equestrian " vice praeses " of Pannonia . However , he is thought to have been prefect during the war with " Persia " initiated by Numerian ' s father , the Emperor Carus and he had probably been given that office at the outset of Carus ' s reign in 282 AD . He is considered likely to have been the unnamed prefect who is said in the " Vita Cari " to have urged Carus to make war on " Persia " , hoping that Carus and Numerian would perish and he himself obtain the Purple . It is thus insinuated , but not directly asserted that he was responsible for the death of both men during and after that campaign . The usual " caveat " s are suggested regarding information based on the Augustan History . The truth is unknowable . What is incontestable is that when Numerian ( who was by that time the Emperor following the death of his father ) died as the Imperial " comitatus " returned from its victorious campaign in " Persia " . Aper was accused of his murder by the army and put on trial . The suspicion of murder evidently arose because Aper had attempted to conceal the fact of Numerian ' s death while he prepared the ground for his own accession to the Purple . Diocles , commander of the " Domestici " ( " Protectores Augusti Nostri " ( ? ) , then gave early proof of the capacity for ruthless and decisive action that was to distinguish him as the Emperor Diocletian by pronouncing Aper the murderer and executing him on the spot by plunging his sword into his breast , thus giving him no chance to justify himself or , perhaps , implicate Diocles . " A charge supported by such decisive proof was admitted without contradiction and the legions with repeated acclamations acknowledged the justice and authority of the Emperor Diocletian " . Aper ' s death is placed in the Autumn of 284 AD .