Aureolus
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For the Frankish ruler of Aragon, see Aureolus of Aragon
.
Manius Acilius Aureolus (died 268) was a Roman
military commander
and would-be usurper
. He was one of the so-called Thirty Tyrants
who populated the reign of the Emperor Gallienus
. Of humble Thraco-Roman
origins, he was 'made' by the Emperor Gallienus and proved himself to be the most brilliant and innovative soldiers of the age. However, he later turned against his benefactor, and was destroyed in the political turmoil that surrounded the Emperor's assassination in a conspiracy orchestrated by his senior officers. The ancient sources which refer to Aureolus are limited and the information they do provide is often contradictory. They include the Historia Augusta, Zonaras
' epitome and Zozimus
' Historia Nova. His career was most recently summarised in John Bray's biography of Gallienus. The analysis of Aureolus's career given here, especially his final rebellion, is largely based on Bray.
, north of the Danube
. It may be conjectured that, like many Dacians, he enlisted in the Roman Army as a young man and had the good fortune to come to the attention of the Emperor Gallienus
. His first job was said to have been as a groom. If so, he must have been a good one, because we first encounter him as Master of the Imperial Horses ('Phronistes') according to Zonaras. The exact meaning of this term is yet unclear. Does it mean that he was Gallienus's Head Groom or does it refer to his later position as commander of Gallienus's cavalry army? (see below). He was said to have been ambidextrous which is doubtless a useful skill for a groom, but may also be a commentary on his untrustworthy character as interpreted by later historians. Throughout his reign Gallienus was always willing to promote talent wherever he found it, and Aureolus was one of the most brilliant of the New Men who were replacing senators in positions of high command in the army in the course of his reign.
as a highly mobile field army under the Emperor's direct control. Aureolus was the first commander of this force under the Emperor. It was based at Mediolanum
(Milan
).
Aureolus first made his mark in history in 258 (or 260 - the date is uncertain) when his cavalry was principally responsible for the defeat of the usurper Ingenuus
at the Battle of Mursa (Osijek in Croatia). In 261 he commanded the force which defeated the army of the usurpers Macrianus Major
and Macrianus Minor
in battle somewhere in the central Balkans. As the army of the Macriani, which was swollen by the garrisons of the Danubian provinces
that were obviously still seething with the resentments that had caused them to support first Ingenuus
and then Regalianus
, was probably at least 30,000 strong it would have required more than Aureolus's cavalry alone to challenge it. In any case Gallienus seems to have given Aureolus a free hand in crushing the rebels and entrusted him with a force that proved sufficient for the purpose. As to why Aureolus is credited with suppressing the Macriani as a major challenge to Gallienus's rule rather than the Emperor himself there are two possible explanations: (1) The determination of the Latin historians to denigrate the achievements of Gallienus; however, a more likely explanation is that (2) Gallienus was attempting at this time to crush the Gallic usurper Postumus
who he probably saw as an even greater threat to his regime than the Macriani and to clear the Juthungi
out of the Alpine province of Raetia
where they posed a direct threat to Italy and Rome. (In any case, Postumus had been principally responsible for the murder of Gallienus's son, the Casear Saloninus
which made their dispute highly personal in a way that with the Macriani was not).
. It may have been as a result of this campaign that the province of Raetia
was recovered from the Gallic Empire (which had driven out the Juthungi where Gallienus seems to have failed) and Postumus's inscription on the Augsburg Altar was erased. However, Postumus managed to evade complete defeat thanks, it was asserted, to the 'carelessness' of Aureolus. It is often implied that even at this stage Aureolus was willing to see Gallienus displaced as Emperor and that he deliberately allowed the Gallic usurper to evade destruction.
Zosimus (1.41) reports that Aureolus and two other officers conspired against Gallienus, but that all of them were punished and submitted, except Aureolus, who retained his anger against the emperor. It is now impossible to determine what lies behind this reference. Perhaps, as a Dacian, Aureolus resented Gallienus's policy of withdrawing elements of the Dacian garrison to reinforce his field army for the defence of Italy thus compounding the problems of barbarian incursions into Dacia. Such resentment may well have enabled Aureolus to persuade himself that Gallienus had forfeited his heaven-sent mandate to rule. However, this is pure speculation unsupported by any direct evidence as to what motivated Aureolus.
At any event, whether or not he indulged in an unsuccessful conspiracy, Aureolus does seem to have lost the confidence of Gallienus as a result of his failure to destroy Postumus in Gaul even though he was not brought to trial nor dismissed the Imperial service for that direlection of duty. He had been given sole responsibility for the campaign against the Macriani, yet when the Goths
and Heruls invaded the Danubian provinces with an enormous force in 268, Aureolus was not even a senior officer of the Imperial comitatus that accompanied the Emperor against the marauders. He was not even left in Milan to mind the shop against Postumus. He seems instead to have been made commander of the Raetian garrison while his cavalry went east with the Emperor under the comamnd of Claudius (later the Emperor Claudius Gothicus) or Aurelian
who also became Emperor in due course.
Losing command of the elite cavalry he had done so much to create and had once led so brilliantly must have seemed a humiliating demotion for Aureolus. That it distinguished itself still further in the campaign against the Goths (especially at the battle of Nessus
(the River Nestus that divided the provinces of Macedonia and Thrace) was no doubt additionally galling. (Post hoc ergo propter hoc (?) Aureolus confirmed his disaffection from Gallienus by deserting his Alpine command, and invading Italy where he took his old base, Milan. This was an act of the very highest treason and meant that Gallienus had to break off his campaign against the Goths in the Balkans at a most critical moment to return to Italy to deal with him. However, it may be that the long-term consequences of Aureolus's rebellion were even more serious in that it opened Raetia to further invasion by the Alamanni
who then went on to raid in force into Italy itelf next year in the early months of the reign of Claudius Gothicus. It may have been at this time that the Agri Decumates
, the Roman lands north-east of the upper Rhine were lost for good.
From Milan Aureolus invited Postumus to challenge Gallienus for the Empire with his support. Using the Imperial mint in Milan he had coins struck bearing Postumus's image as Emperor with appeals to the faith of his former comrades of the cavalry on the reverse. This seems to have been Aureolus's idea alone for Postumus never tried to suborn the loyalty of the cavalry in this way.
In any event, Postumus ignored his invitation and Aureolus, unsupported by the Gallic usurper, was defeated by Gallienus in a battle on the River Adda east of Milan at a place still known as Pontirolo Nuovo
- i.e. 'The New Bridge of Aureolus'. He was then besieged in Milan which was invested by Gallienus's military comitatus (including, it would seem, the cavalry which Aureolus had been largely instrumental in creating and to loyalty of which he now appealed in vain).
It cannot be certain what Aureolus's motives were in staging his desperate coup against Gallienus. It may have been sheer resentment at his demotion after the unsuccessful attack on Postumus combined with a belief that Gallienus's military policies had undermined the defences of Dacia and the Illyrian provinces. Admittedly, if indeed he had deliberately let Postumus off the hook, he would have been very lucky to escape with his life under almost any other Roman Emperor rather than be rewarded with another significant command. Military ambition quite often exceeded gratitude in Gallienus's reign. However, the conspiracy by the Praetorian Prefect, together with Aurelius Heraclianus, Claudius and Aurelian
that was to cost Gallienus his life suggests that there was a growing belief at the highest level of the army in the later 260s that the Emperor was no longer fit to rule and Aureolus may well have shared these sentiments.
Aureolus's end came when he surrendered to Claudius Gothicus who had by this time succeeded Gallienus as Emperor after the latter was assassinated in a 'Marshals' Plot' in which Claudius was almost certainly a prime mover.
However, apparently before Claudius could decide what to do with him, Aureolus was murdered by Claudius's Praetorian Guard
, supposedly in revenge for Aureolus's rebellion against Gallienus which had evoked great fury in the ranks of the Imperial comitatus which obviously did not share the treasonable disloyalty to that Emperor's regime of its most senior officers.
The question might be asked, if they were thus infuriated by Aureolus who had merely rebelled against Gallienus - something a good many self-respecting senior soldiers had attempted during his turbulemt reign - why did they not exact similar vengeance on his actual murderers? It could well be that the moral authority over the army exercised by Claudius, Heraclianus, Aurelian et al. who, however tainted by treason, had at least shown themselves as resolute defenders of the Empire in numerous wars against its barbaric foes, was of a different order to that enjoyed by Aureolus after his suspicious failure to finish off Postumus after his victory over the Macriani.
However, it is also possible to suggest that the action of Claudius's Pratorians in taking it upon themselves to dispose of Aureolus would have been very convenient if their master wanted to obliterate any evidence of treasonable links between Aureolus and Gallienus's murderers. Against this one might wander why Gallienus's treachorous marshals would see any benefit in associating themselves with damaged goods such as Aureolus.
Sometimes the simplest explanations are most persuasive. Aureolus was murdered by furious soldiers who were then persuaded to turn a blind eye to the likely greater culpability of their new leader - no doubt convinced in the end by the generous donative he was able to offer them.
In the end we do not know and will never know what motivated the men of the Imperial Comitatus or their leaders in 268 AD.
Aureolus of Aragon
Aureolus is traditionally thought to have been the chief of the Franks in the region of Aragón.Between 798 and 802 the Franks established several positions in the zone: Bahlul Ibn Marzuq revolted in Zaragoza against the central government of Muslim Al-Andalus in 798, and in 800 conquered Huesca...
.
Manius Acilius Aureolus (died 268) was a Roman
Roman Empire
The Roman Empire was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean....
military commander
Roman army
The Roman army is the generic term for the terrestrial armed forces deployed by the kingdom of Rome , the Roman Republic , the Roman Empire and its successor, the Byzantine empire...
and would-be usurper
Usurper
Usurper is a derogatory term used to describe either an illegitimate or controversial claimant to the power; often, but not always in a monarchy, or a person who succeeds in establishing himself as a monarch without inheriting the throne, or any other person exercising authority unconstitutionally...
. He was one of the so-called Thirty Tyrants
Thirty Tyrants (Roman)
The Thirty Tyrants were a series of thirty rulers that appear in the Historia Augusta as having ostensibly been pretenders to the throne of the Roman Empire during the reign of the emperor Gallienus....
who populated the reign of the Emperor Gallienus
Gallienus
Gallienus was Roman Emperor with his father Valerian from 253 to 260, and alone from 260 to 268. He took control of the Empire at a time when it was undergoing great crisis...
. Of humble Thraco-Roman
Thraco-Roman
The terms Thraco-Roman and Daco-Roman refer to the culture and language of the Thracian and Dacian peoples who were incorporated into the Roman Empire and ultimately fell under the Roman and Latin sphere of influence.-Meaning and usage:...
origins, he was 'made' by the Emperor Gallienus and proved himself to be the most brilliant and innovative soldiers of the age. However, he later turned against his benefactor, and was destroyed in the political turmoil that surrounded the Emperor's assassination in a conspiracy orchestrated by his senior officers. The ancient sources which refer to Aureolus are limited and the information they do provide is often contradictory. They include the Historia Augusta, Zonaras
Joannes Zonaras
Ioannes Zonaras was a Byzantine chronicler and theologian, who lived at Constantinople.Under Emperor Alexios I Komnenos he held the offices of head justice and private secretary to the emperor, but after Alexios' death, he retired to the monastery of St Glykeria, where he spent the rest of his...
' epitome and Zozimus
Zozimus
Michael J. Moran , popularly known as Zozimus, was an Irish street rhymer. He was a resident of Dublin and also known as the "Blind Bard of the Liberties" and the "Last of the Gleemen".-Biography:...
' Historia Nova. His career was most recently summarised in John Bray's biography of Gallienus. The analysis of Aureolus's career given here, especially his final rebellion, is largely based on Bray.
Early life and career
There is no way of determining his date of birth, but given that he was at the height of his powers in the later 250s and 260s AD he is likely to have been born by 230 at the latest. Zonaras says that he was a herdsman born in the Roman province of DaciaDacia
In ancient geography, especially in Roman sources, Dacia was the land inhabited by the Dacians or Getae as they were known by the Greeks—the branch of the Thracians north of the Haemus range...
, north of the Danube
Danube
The Danube is a river in the Central Europe and the Europe's second longest river after the Volga. It is classified as an international waterway....
. It may be conjectured that, like many Dacians, he enlisted in the Roman Army as a young man and had the good fortune to come to the attention of the Emperor Gallienus
Gallienus
Gallienus was Roman Emperor with his father Valerian from 253 to 260, and alone from 260 to 268. He took control of the Empire at a time when it was undergoing great crisis...
. His first job was said to have been as a groom. If so, he must have been a good one, because we first encounter him as Master of the Imperial Horses ('Phronistes') according to Zonaras. The exact meaning of this term is yet unclear. Does it mean that he was Gallienus's Head Groom or does it refer to his later position as commander of Gallienus's cavalry army? (see below). He was said to have been ambidextrous which is doubtless a useful skill for a groom, but may also be a commentary on his untrustworthy character as interpreted by later historians. Throughout his reign Gallienus was always willing to promote talent wherever he found it, and Aureolus was one of the most brilliant of the New Men who were replacing senators in positions of high command in the army in the course of his reign.
With Gallienus
As Imperial Horsemaster Aureolus would have been well-placed to work with Gallienus in formulating and developing the concept of a self-contained cavalry force to beef up the effectiveness of the comitatusComitatenses
Comitatenses is the Latin plural of comitatensis, originally the adjective derived from comitatus , itself rooting in Comes .However, historically it became the accepted name for...
as a highly mobile field army under the Emperor's direct control. Aureolus was the first commander of this force under the Emperor. It was based at Mediolanum
Mediolanum
Mediolanum, the ancient Milan, was an important Celtic and then Roman centre of northern Italy. This article charts the history of the city from its settlement by the Insubres around 600 BC, through its conquest by the Romans and its development into a key centre of Western Christianity and capital...
(Milan
Milan
Milan is the second-largest city in Italy and the capital city of the region of Lombardy and of the province of Milan. The city proper has a population of about 1.3 million, while its urban area, roughly coinciding with its administrative province and the bordering Province of Monza and Brianza ,...
).
Aureolus first made his mark in history in 258 (or 260 - the date is uncertain) when his cavalry was principally responsible for the defeat of the usurper Ingenuus
Ingenuus
Ingenuus was a Roman military commander, the imperial legate in Pannonia, who became a usurper to the throne of the emperor Gallienus when he led a brief and unsuccessful revolt in the year 260. Appointed by Gallienus himself, Ingenuus served him well by repulsing a Sarmatian invasion and securing...
at the Battle of Mursa (Osijek in Croatia). In 261 he commanded the force which defeated the army of the usurpers Macrianus Major
Macrianus Major
Fulvius Macrianus , also called Macrianus Major, was a Roman usurper. He was one of Valerian's fiscal officers. More precisely, sources refer to him as being in charge of the whole state accounts or, in the language of a later age, as Count of the Treasury and the person in charge of markets and...
and Macrianus Minor
Macrianus Minor
Titus Fulvius Iunius Macrianus , also known as Macrianus Minor, was a Roman usurper. He was the son of Fulvius Macrianus, also known as Macrianus Major.- Career :...
in battle somewhere in the central Balkans. As the army of the Macriani, which was swollen by the garrisons of the Danubian provinces
Danubian provinces
Danubian provinces to refer to the Roman provinces of the Lower Danube: Dacia , Moesia and Scythia Minor, as well as Pannonia Inferior....
that were obviously still seething with the resentments that had caused them to support first Ingenuus
Ingenuus
Ingenuus was a Roman military commander, the imperial legate in Pannonia, who became a usurper to the throne of the emperor Gallienus when he led a brief and unsuccessful revolt in the year 260. Appointed by Gallienus himself, Ingenuus served him well by repulsing a Sarmatian invasion and securing...
and then Regalianus
Regalianus
P. C Regalianus was a Dacian general who turned against the Roman Empire and became himself emperor for a brief period, being murdered by the hands who raised him to power.-Career:...
, was probably at least 30,000 strong it would have required more than Aureolus's cavalry alone to challenge it. In any case Gallienus seems to have given Aureolus a free hand in crushing the rebels and entrusted him with a force that proved sufficient for the purpose. As to why Aureolus is credited with suppressing the Macriani as a major challenge to Gallienus's rule rather than the Emperor himself there are two possible explanations: (1) The determination of the Latin historians to denigrate the achievements of Gallienus; however, a more likely explanation is that (2) Gallienus was attempting at this time to crush the Gallic usurper Postumus
Postumus
Marcus Cassianius Latinius Postumus was a Roman emperor of Batavian origin. He usurped power from Gallienus in 260 and formed the so-called Gallic Empire...
who he probably saw as an even greater threat to his regime than the Macriani and to clear the Juthungi
Juthungi
The Juthungi were a Germanic tribe in the region north of the rivers Danube and Altmühl in the modern German state of Bavaria....
out of the Alpine province of Raetia
Raetia
Raetia was a province of the Roman Empire, named after the Rhaetian people. It was bounded on the west by the country of the Helvetii, on the east by Noricum, on the north by Vindelicia, on the west by Cisalpine Gaul and on south by Venetia et Histria...
where they posed a direct threat to Italy and Rome. (In any case, Postumus had been principally responsible for the murder of Gallienus's son, the Casear Saloninus
Saloninus
Publius Licinius Cornelius Saloninus Valerianus was Roman Emperor in 259 or 260.-Early life:Saloninus was born around the year 242. His father was the later emperor Gallienus, his mother Cornelia Salonina, a Greek from Bithynia...
which made their dispute highly personal in a way that with the Macriani was not).
Against Gallienus
After the Macriani were defeated and the Danubian garrison forces who had supported them were pacified, Aureolus accompanied the Emperor in (another?) attempt to crush Postumus and his Gallic EmpireGallic Empire
The Gallic Empire is the modern name for a breakaway realm that existed from 260 to 274. It originated during the Roman Empire's Crisis of the Third Century....
. It may have been as a result of this campaign that the province of Raetia
Raetia
Raetia was a province of the Roman Empire, named after the Rhaetian people. It was bounded on the west by the country of the Helvetii, on the east by Noricum, on the north by Vindelicia, on the west by Cisalpine Gaul and on south by Venetia et Histria...
was recovered from the Gallic Empire (which had driven out the Juthungi where Gallienus seems to have failed) and Postumus's inscription on the Augsburg Altar was erased. However, Postumus managed to evade complete defeat thanks, it was asserted, to the 'carelessness' of Aureolus. It is often implied that even at this stage Aureolus was willing to see Gallienus displaced as Emperor and that he deliberately allowed the Gallic usurper to evade destruction.
Zosimus (1.41) reports that Aureolus and two other officers conspired against Gallienus, but that all of them were punished and submitted, except Aureolus, who retained his anger against the emperor. It is now impossible to determine what lies behind this reference. Perhaps, as a Dacian, Aureolus resented Gallienus's policy of withdrawing elements of the Dacian garrison to reinforce his field army for the defence of Italy thus compounding the problems of barbarian incursions into Dacia. Such resentment may well have enabled Aureolus to persuade himself that Gallienus had forfeited his heaven-sent mandate to rule. However, this is pure speculation unsupported by any direct evidence as to what motivated Aureolus.
At any event, whether or not he indulged in an unsuccessful conspiracy, Aureolus does seem to have lost the confidence of Gallienus as a result of his failure to destroy Postumus in Gaul even though he was not brought to trial nor dismissed the Imperial service for that direlection of duty. He had been given sole responsibility for the campaign against the Macriani, yet when the Goths
Goths
The Goths were an East Germanic tribe of Scandinavian origin whose two branches, the Visigoths and the Ostrogoths, played an important role in the fall of the Roman Empire and the emergence of Medieval Europe....
and Heruls invaded the Danubian provinces with an enormous force in 268, Aureolus was not even a senior officer of the Imperial comitatus that accompanied the Emperor against the marauders. He was not even left in Milan to mind the shop against Postumus. He seems instead to have been made commander of the Raetian garrison while his cavalry went east with the Emperor under the comamnd of Claudius (later the Emperor Claudius Gothicus) or Aurelian
Aurelian
Aurelian , was Roman Emperor from 270 to 275. During his reign, he defeated the Alamanni after a devastating war. He also defeated the Goths, Vandals, Juthungi, Sarmatians, and Carpi. Aurelian restored the Empire's eastern provinces after his conquest of the Palmyrene Empire in 273. The following...
who also became Emperor in due course.
Losing command of the elite cavalry he had done so much to create and had once led so brilliantly must have seemed a humiliating demotion for Aureolus. That it distinguished itself still further in the campaign against the Goths (especially at the battle of Nessus
Nessus
Nessus can have a number of meanings:* Nessus , a famous centaur from Greek mythology* The Tunic or Shirt of Nessus, the poisoned shirt of the centaur Nessus, in the story of Hercules...
(the River Nestus that divided the provinces of Macedonia and Thrace) was no doubt additionally galling. (Post hoc ergo propter hoc (?) Aureolus confirmed his disaffection from Gallienus by deserting his Alpine command, and invading Italy where he took his old base, Milan. This was an act of the very highest treason and meant that Gallienus had to break off his campaign against the Goths in the Balkans at a most critical moment to return to Italy to deal with him. However, it may be that the long-term consequences of Aureolus's rebellion were even more serious in that it opened Raetia to further invasion by the Alamanni
Alamanni
The Alamanni, Allemanni, or Alemanni were originally an alliance of Germanic tribes located around the upper Rhine river . One of the earliest references to them is the cognomen Alamannicus assumed by Roman Emperor Caracalla, who ruled the Roman Empire from 211 to 217 and claimed thereby to be...
who then went on to raid in force into Italy itelf next year in the early months of the reign of Claudius Gothicus. It may have been at this time that the Agri Decumates
Agri Decumates
The agri decumates or decumates agri were a region of the Roman Empire's province of Germania superior , covering the Black Forest area between the Main river and the sources of Danube and Rhine rivers, presently in Southwestern Germany...
, the Roman lands north-east of the upper Rhine were lost for good.
From Milan Aureolus invited Postumus to challenge Gallienus for the Empire with his support. Using the Imperial mint in Milan he had coins struck bearing Postumus's image as Emperor with appeals to the faith of his former comrades of the cavalry on the reverse. This seems to have been Aureolus's idea alone for Postumus never tried to suborn the loyalty of the cavalry in this way.
In any event, Postumus ignored his invitation and Aureolus, unsupported by the Gallic usurper, was defeated by Gallienus in a battle on the River Adda east of Milan at a place still known as Pontirolo Nuovo
Pontirolo Nuovo
Pontirolo Nuovo is a comune in the Province of Bergamo in the Italian region of Lombardy, located about 40 km northeast of Milan and about 18 km norheast of Bergamo...
- i.e. 'The New Bridge of Aureolus'. He was then besieged in Milan which was invested by Gallienus's military comitatus (including, it would seem, the cavalry which Aureolus had been largely instrumental in creating and to loyalty of which he now appealed in vain).
It cannot be certain what Aureolus's motives were in staging his desperate coup against Gallienus. It may have been sheer resentment at his demotion after the unsuccessful attack on Postumus combined with a belief that Gallienus's military policies had undermined the defences of Dacia and the Illyrian provinces. Admittedly, if indeed he had deliberately let Postumus off the hook, he would have been very lucky to escape with his life under almost any other Roman Emperor rather than be rewarded with another significant command. Military ambition quite often exceeded gratitude in Gallienus's reign. However, the conspiracy by the Praetorian Prefect, together with Aurelius Heraclianus, Claudius and Aurelian
Aurelian
Aurelian , was Roman Emperor from 270 to 275. During his reign, he defeated the Alamanni after a devastating war. He also defeated the Goths, Vandals, Juthungi, Sarmatians, and Carpi. Aurelian restored the Empire's eastern provinces after his conquest of the Palmyrene Empire in 273. The following...
that was to cost Gallienus his life suggests that there was a growing belief at the highest level of the army in the later 260s that the Emperor was no longer fit to rule and Aureolus may well have shared these sentiments.
Death
When Gallienus was murdered it is possible Aureolus made his own bid for the Purple if a rather obscure issue of coinage is to be believed. However, as Aureolus had earlier offered his allegiance to Postumus it seems likely that he made this last defiant gesture - if indeed he did make it - only when Postumus failed to take advantage of the turmoil in Italy.Aureolus's end came when he surrendered to Claudius Gothicus who had by this time succeeded Gallienus as Emperor after the latter was assassinated in a 'Marshals' Plot' in which Claudius was almost certainly a prime mover.
However, apparently before Claudius could decide what to do with him, Aureolus was murdered by Claudius's Praetorian Guard
Praetorian Guard
The Praetorian Guard was a force of bodyguards used by Roman Emperors. The title was already used during the Roman Republic for the guards of Roman generals, at least since the rise to prominence of the Scipio family around 275 BC...
, supposedly in revenge for Aureolus's rebellion against Gallienus which had evoked great fury in the ranks of the Imperial comitatus which obviously did not share the treasonable disloyalty to that Emperor's regime of its most senior officers.
The question might be asked, if they were thus infuriated by Aureolus who had merely rebelled against Gallienus - something a good many self-respecting senior soldiers had attempted during his turbulemt reign - why did they not exact similar vengeance on his actual murderers? It could well be that the moral authority over the army exercised by Claudius, Heraclianus, Aurelian et al. who, however tainted by treason, had at least shown themselves as resolute defenders of the Empire in numerous wars against its barbaric foes, was of a different order to that enjoyed by Aureolus after his suspicious failure to finish off Postumus after his victory over the Macriani.
However, it is also possible to suggest that the action of Claudius's Pratorians in taking it upon themselves to dispose of Aureolus would have been very convenient if their master wanted to obliterate any evidence of treasonable links between Aureolus and Gallienus's murderers. Against this one might wander why Gallienus's treachorous marshals would see any benefit in associating themselves with damaged goods such as Aureolus.
Sometimes the simplest explanations are most persuasive. Aureolus was murdered by furious soldiers who were then persuaded to turn a blind eye to the likely greater culpability of their new leader - no doubt convinced in the end by the generous donative he was able to offer them.
In the end we do not know and will never know what motivated the men of the Imperial Comitatus or their leaders in 268 AD.