sentences:  There he proved his loyalty to Trajan; as a consequence, Trajan appointed him commander of the Praetorian Guard.His predecessor, Casperius Aelianus, had been responsible for an insurrection against the previous emperor Nerva; following emperor Nerva's death, Casperius and others involved in the mutiny were summoned before Trajan at his headquarters in Colonia Agrippina under false pretenses where, in the words of Cassius Dio, Trajan "put them out of the way".In the opinion of the historian John D. Grainger, the manner in which Casperius was dispatched left the rest of the men in the Praetorian Guard "surely very resentful at the execution of their officers and colleagues and at the deceitful way it had been accomplished."