It was said that the terms of resignation had actually been agreed upon with Primus, one of Vespasian's chief supporters, but the praetorians refused to allow him to carry out the agreement, and forced him to return to the palace, when he was on his way to deposit the insignia of empire in the temple of Concord.
15) and Achilleus, said to have been baptized by St Peter, refused to do the bidding of Domitian as praetorians, and entering the service of Flavia Domitilla, suffered martyrdom with their mistress Petronilla, of the Aurelian family closely connected with the Flavii, and the spiritual daughter of St Peter, who was buried in a sarcophagus with the inscription: [[Avreliae Petronillae Fil Dvlcissimae]] This is now in St Peter's, but was probably originally behind the apse of this basilica, for there is a fresco of her in an arcosolium, with a matron named Veneranda.
In his dealings with the mutinous praetorians the strength of the new emperor's hand was shown at once.
The attempt also of the daring highwayman Maternus to seize the empire was betrayed; but at last Eclectus the emperor's chamberlain, Laetus the praefect of the praetorians, and his mistress Marcia, finding their names on the list of those doomed to death, united to destroy him.
Under the empire the praetorians or imperial guards were commanded by one, two, or even three praefects (praefecti praetorio), who were chosen by the emperor from among the knights and held office at his pleasure.