2nd c. CE

Although no foul play could be linked to Nerva’s death in 98 CE, Trajan had the surviving Praetorian Prefect executed all the same.  Wary of returning too soon to Rome, Trajan lingered in his former province, making plans to conclude what Domitian had begun – the conquest of Dacia.  About this time, a new arm of elite household troops was formed: the Equites Singulares Augusti, picked cavalrymen from auxiliary units stationed throughout the Empire.  Along with the Praetorian cavalry (the speculatores) the Singulares formed the Emperor’s mounted escort.

The Praetorians were to play a significant role in Trajan’s Dacian invasions of 101-102 and 105-106 CE.  For their excellent service, the Emperor rewarded them with eternal recognition on his monumental column that is still standing today in Rome.  The Praetorians also accompanied Trajan on his campaigns against the Parthians on the eastern frontiers.

Through the 2nd c. CE, the Praetorians continued to serve on campaigns abroad, reinforcing their loyalty to the Roman state and keeping their officers too well-occupied to pursue personal agendas.  Both Lucius Verus and Marcus Aurelius brought a Praetorian contingent with them on their campaigns in the East and North, where the Guard fought heavily, losing two more Prefects in combat.

But Marcus Aurelius’ incapable son Commodus, who succeeded his father in 180 CE, did not continue the forward defensive policy pursued by his wiser predecessors.  The legions languished near dormancy in their frontier bases, while the Praetorians withdrew to their camp in Rome to grow bored and corrupt once more.

After five years of weak rule, Commodus disposed of his overeager Prefect Perrenis, while his freedman, Cleander, exerted a growing influence over the administration of the Empire due to Commodus’ lack of interest.  Cleander even convinced Commodus to appoint him as co-Prefect alongside the two legitimate Prefects.  Cleander promptly abused his new power by ordering the Equites Singulares to slay dissident Roman civilians.  The incident led to a confused street battle between the Singulares and the Urban Cohorts, Rome’s police force.

The removal of Cleander in 192 did Commodus no good, for shortly thereafter the Prefect Laetus murdered the vainglorious Emperor and placed his co-conspirator, Pertinax, on the throne.  Pertinax tried to buy the loyalty of the Praetorian Guard with a bounty of 3,000 denarii, but the surly Guard barely tolerated him for three months before assassinating him.