The Pinnacle of Power
All this means that Plautianus had to be with the emperor nearly all the time. He certainly accompanied Severus to Egypt and must have joined the imperial family's Nile cruise to Thebes. However, his power and physical presence made a clash with Severus' relatives inevitable. Dio mentions that Plautianus "cordially detested" Julia Domna, abused her violently to Severus, conducted investigations into her private life, and that "for this reason she began to study philosophy and passed her days in company with sophists".note[Cassius Dio, Roman History, 76.15.] Again, we have to take Dio's bias into account - he even claims that Plautianus had several ladies tortured to find out about the empress' conduct - but we're at least certain that the praetorian prefect was exceptionally powerful, and that the emperor chose to accept it.
Probably in 201, Plautianus' daughter Plautilla was engaged to Caracalla, who was by now fourteen or fifteen years old. The move may have been designed by Severus to take away the opposition between his family and the prefect, by creating a shared interest. The wedding was scheduled for April 203, when Severus would celebrate his decennalia, the tenth anniversary of his coming to power. Because Plautianus was an equestrian, he first had to receive a real consulship, because otherwise, Caracalla would marry below his rank.
Plautianus entered upon the consulship on 1 January 203; his colleague was Publius Septimius Geta, the brother of the emperor. (Because Plautianus already possessed the ornamenta consularia, it was recorded as his second term.) At that moment, the imperial court was in Africa, in Lepcis Magna, and Plautianus had in the meantime probably led an attack on the Garamantes. In Lepcis, several statues and busts were erected for the war hero and consul, who was, together with Severus himself, the city's most famous son. This, however, was more than the emperor found acceptable, and he ordered the removal of these sculptures.note[Cassius Dio, Roman History 76.16; the Historia Augusta, 14.5, suggests that this incident took place earlier.]
In spite of this incident, Plautianus kept the emperor's confidence and the wedding was celebrated. He was also involved in the olive oil trade that was established in these years, when the Limes Tripolitanus was created. It must have contributed to his wealth, and it comes as no surprise that in 204, we find him as one of the organizers of the Secular Games, an office that must have involved considerable expenditure.
Yet, Plautianus' downfall was inevitable. The marriage between Plautilla and Caracalla was a disaster, which meant that the emperor's family - i.e., Caracalla - and the praetorian prefect remained rivals. Dio records two traditions, which he connects rather awkwardly. In the first one, he states that Publius Septimius Geta, on his deathbed ("he now no longer feared Plautianus"), convinced his brother that he ought to curtail Plautianus' power. Understanding that his brother was right, the emperor "no longer held his minister in the same honor, but stripped him of most of his power, and hence Plautianus became very indignant".note[Cassius Dio, Roman History 77.2.4-5.]
The awkward connection is that Plautianus became angry at Caracalla, who had nothing to do with Geta's remarks. Dio now switches to another tradition, in which Caracalla "conceived the desire to get rid of him in some way or other".note[Cassius Dio, Roman History 77.3.1.] Through his teacher Euodius, he recruited three centurions, who presented themselves to Septimius Severus, claiming that Plautianus had ordered the assassination of the emperor, and presenting a letter that seemed to confirm this. It was 22 January 205. Severus immediately summoned his prefect to explain himself.
He talked to him in a very mild manner, and asked: "Why have you seen fit to do this? Why did you wish to kill us?"
He also gave him an opportunity to speak and acted as if intending to listen to his defense. But Caracalla, as Plautianus was making denial and expressing amazement at what was said, rushed up, took away his sword, and struck him with his fist; and he even wanted to kill him with his own hands.
But, being prevented by his father, Caracalla ordered one of the attendants to slay Plautianus. And somebody plucked out a few hairs from his beard, carried them to Julia Domna and Plautilla, who were together, before they had heard a word of the affair, and exclaimed, "Behold your Plautianus," thus causing grief to the one and joy to the other.note[Cassius Dio, Roman History 77.4.2-4; tr. E. Cary.]
Dio makes it clear that he does not believe that Plautianus had really given written orders to kill the emperor,note[Cassius Dio, Roman History 77.3.4.] but was to some extent influenced by the official version, because he mentioned that Plautianus had become indignant. This version, that the prefect had really started to conspire against the emperor after his powers had been curtailed, was believed unquestionably by Herodian.note[Herodian, History of the Roman Empire 3.11.]
Dio remarks that Severus allowed the funeral of Plautianus and that he refused to accuse the praetorian prefect in the Senate. There was a formal hearing, several friends of Plautianus were put to death, and his memory was officially cursed. However, the praefectus urbi, Fabius Cilo, could intervene on behalf of a capable man like Marcus Opellius Macrinus, and there was no purge. Both Plautilla and her brother, Gaius Fulvius Plautianus Hortensianus, remained alive: they were exiled to Lipara, one of the Aeolian Islands. Severus must have understood that he would either lose his right-hand man or his son, and he appears to have accepted what had been inevitable.
The death of Plautianus created opportunities, for better and worse. For better: the road was now free for people whose career had until now been obstructed, like Julia Domna's relatives Avitus Alexianus and Varius Marcellus, who would indeed occupy important positions, and would guarantee the continuity of the dynasty after the death of Caracalla (in 217). On the other hand, it was now also obvious that Caracalla was to succeed to the throne, which he did in 211. As Dio says, the young ruler and his brother Geta, "feeling that they had got rid of a pedagogue, as it were, in Plautianus, now went to all lengths in their conduct. They outraged women and abused boys, they embezzled money, and made gladiators and charioteers their boon companions".note[Cassius Dio, Roman History 77.7.1.]
Plautianus' legacy, however, was more substantial than just the obstruction of the career of several men. He had in fact created a new type of praetorian prefecture: not longer was the praefectus praetorio the commander of the guard, he was also responsible for the Second Parthian Legion, the new strategic reserve of the Empire. The juridical powers had also been expanded and the prefect had become a permanent member of the consilium principis, the emperor's advisory board. The future would see many changes in government, but the powerful praetorian prefects were to guarantee some kind of continuity.
- A.R. Birley, Septimius Severus. The African Emperor (1988²)
- J. Spielvogel, Septimius Severus (2006)