The scattered Praetorian encampments inside the city are centralized into a single garrison just outside Rome in 20 and the number of cohorts is increased from nine to twelve, one of which now holds the daily guard at the palace.

The practice of joint leadership between two prefects is abandoned, and Sejanus himself appoints he centurions and tribunes.

With these changes in effect, Sejanus now commands the complete loyalty of a force of around twelve thousand soldiers, all of which are at his immediate disposal.

The facade of Augustus is no longer maintained, and Tiberius openly displays the strength of the guard at parades.