Soon after, Tacitus appointed Florianus as praetorian prefect. Constantine subdivided the empire into four Praetorian prefectures. In 288, Maximian appointed Constantius to serve as his praetorian prefect in Gaul. Claudius became emperor after procuring the support of the Praetorian Guard. In his capacity as Praetorian prefect, Sejanus quickly became a trusted advisor to Tiberius. The Romans had used the term to describe officials subordinate to the praetorian prefects. Like Claudius, Nero became emperor with the consent of the Praetorian Guard. Starting from Vespasian, whose son, Titus was himself a Praetorian prefect, they were ranked first. Properly it was a role that belonged to the praetorian prefect. The empire was subdivided into four praetorian prefectures. The Dacias were still divided in three, governed by a praetorian senator and two procurators. Elagabalus and his mother were murdered in a Praetorian Guard camp mutiny. Elagabalus and his mother were then assassinated in a Praetorian Guard camp mutiny. At the level of the Praetorian Prefectures sat the five Patriarchates. This edict is also known as praetorian law.