Servian Wall
From the reign of Tiberius, their camp was situated on the Quirinal Hill, outside Rome. In 26 AD, Sejanus, Praetorian prefect, and the favorite of emperor Tiberius, united the Urban Cohorts with nine Praetorian Cohorts, dispersed at that time throughout Italy, in one large camp situated beyond the Servian Wall, on the Esquiline Hill, the "Castra Praetoria".