Why were four Roman senators executed early in Hadrian’s reign?

Early in Hadrian’s reign, four Roman senators of exalted, consular rank were executed for alleged conspiracy. These men were specifically identified as generals associated with the military ventures of the previous emperor, Trajan.12

The executions were ordered by Acilius Attianus, the prefect of the Praetorian Guard, while he was directing affairs in Rome before Hadrian’s return to the city. These individuals were perceived as threats to the security of the new regime.1

Following the event, Hadrian publicly distanced himself from the actions, claiming that the executions were carried out by Attianus against his wishes and without his direct authorization. Upon his arrival in Rome in 118, Hadrian eventually dismissed Attianus from his position.12