Apart from the praetorians, the first emperors, starting with Octavian Augustus and ending with Galba, had a bodyguard formation that was in some way much more closely related to them than the praetorians. It is about the Germanic bodyguard (germani corpore custodes). Members of this unit came from the Germanic Ubi and Batava tribes. Their standard number is about 300 people (from 100 to 500 people). The beginning of their existence falls during the period of success of the emperor Tiberius in Germany. it was then Augustus decided to appoint a bodyguard from the loyal Germans.
The end of the existence of this formation was put by the emperor Galba in 68 CE. As Suetonius writes:
(…) dissolved the Germanic cohort, which had been tried in many cases of fidelity in many cases, to be guarded by the Caesars, and sent it back to his homeland without any compensation on the accusation that it was more Gn. Dolabelli (…)
– Suetonius, Galba, 12
In terms of organization, the Germanic bodyguard was divided into decuriae, commanded by the decurions. On the other hand, the decuriae were part of a cohort (cohors Germanorum), which was probably mixed (cohors equitata). It consisted of both riders and pedestrians, and more precisely people who could serve in this capacity. The commander of this unit could be called: tribunus Germanorum corpore custodum or: curator Germanorum. The Germanic bodyguard was a formation distinct from the Praetorian Guard. Its status can be defined as appropriate for a private and unofficial entity. This meant that only the emperor had the right to appoint or dissolve it. He also had to decide on the recruitment of people to serve in Germani corpore custodes, their number, tasks and remuneration. The emperor could personally lead this formation. He could also appoint commanders directly subordinate to his orders. The Germani corpore custodes thus had the status of an independent formation not under the direct authority of the Prefects of the Praetorian Guard. The seat of Germani corpore custodes in Rome was a fort that was located on the outskirts of the city on the west side of the Tiber at Via Portunensis.
In place of Germani corpore custodes, probably during the reign of Domitian, and certainly during the reign of Trajan, there appeared equites singulares Augusti. The lineage of this formation should be linked to the mounted units of the bodyguard at the disposal of the governors of the Roman provinces (equites singulares). The soldiers who made up equites singulares Augusti were people without Roman citizenship. They came from mounted auxiliaries (alae), from which, after a period of several years of service, they could be transferred to Rome. Equites singulares Augusti formed an independent numerus with initially 1000 riders. During the reign of Septimius Severus, a second branch of equites singulares Augusti was created, hence the number of horsemen increased to 2000. These two branches were divided, like Germani corpore custodes, into decades headed by the standing decurions. These, however, were under the authority of two tribunes who were the commanders of these two divisions. The formation equites singulares Augusti was stationed in two camps (“old” and “new”) located near the Lateran in Rome. The service time in this unit, as in the auxiliary units, was 25 years. The formation of equites singulares Augusti was disbanded in 312 CE.