Pertinax narrowly averts one conspiracy by a group to replace him with the consul Quintus Sosius Falco while he is in Ostia inspecting the arrangements for grain shipments.

The plot is betrayed in early March; Falco himself is pardoned but several of the officers behind the coup are executed.

Pertinax is at his palace on March 28, 193, when, according to the Historia Augusta, a contingent of some three hundred soldiers of the Praetorian Guard rushes the gates (two hundred according to Cassius Dio).

Ancient sources suggest that they had received only half their promised pay.

Neither the guards on duty nor the palace officials choose to resist them.

Pertinax sends Laetus to meet them, but he chooses to side with the insurgents instead and deserts the emperor.

Although advised to flee, Pertinax then attempts to reason with them, and is almost successful before being struck down by one of the soldiers.

Pertinax must have been aware of the danger he faced by assuming the purple, for he refused to use imperial titles for either his wife or son, thus protecting them from the aftermath of his own assassination.

Immediately after the murder of Pertinax, the Praetorian assassins announce that the throne is to be sold to the man who will pay the highest price.

Titus Flavius Sulpicianus, prefect of the city, father-in-law of the murdered emperor, being at this moment in the camp to which he had been sent to calm the troops, begins making offers when Didius Julianus, having been roused from a banquet by his wife and daughter, arrives in all haste, and being unable to gain admission, stands before the gate, and with a loud voice competes or the prize.

Julianus, consul in 175 along with Pertinax, had further distinguished himself in a campaign against the Chatti, ruled Dalmatia and Germania Inferior, and then was made prefect charged with distributing money to the poor of Italy.

It was around this time that he had been charged with having conspired against the life of Commodus, but he had had the good fortune to be acquitted and to witness the punishment of his accuser.

After governing Bithynia, he had succeeded Pertinax in 190 as the proconsul of Africa.

As the bidding goes on, the soldiers report to each of the two competitors, the one within the fortifications, the other outside the rampart, the sum offered by his rival.

Eventually Sulpicianus promises 20,000 sesterces to every soldier; Julianus, fearing that Sulpicianus will gain the throne, then offers 25,000.

The guards immediately close with the offer of Julianus, throw open the gates, salute him by the name of Commodus, and proclaim him emperor.

Threatened by the military, the Senate declares him emperor.

His wife and his daughter both receive the title Augusta.