Count Theodosius

[5] After restoring order in Britain he returned to continental Europe and fought against the Alemanni; as Valentinian's magister equitum (Master of Horse) he successfully invaded Alemannic territory (371 or 370).

"companion [of the emperor] for military affairs"; the word comes is the origin of the medieval European feudal title of count and its homologues.

Theodosius was given command of part of Valentinian's comitatensis (the Imperial Field Army) and early in the year he marched on Bononia (Boulogne-sur-Mer), Rome's harbour on the Channel.

When his army finally crossed the Channel with the onset of favorable spring weather, Theodosius had made his plans and was ready to move.

Using Londinium as his base of operations, Theodosius divided his army into detachments and sent them to attack bands of marauders within reach of the city.

[16][17] Over the winter of 368–369, large numbers of troops drifted back into their units, bringing vital intelligence that would help Theodosius plan the next phase of his campaign.

[20][21] On his return from Britain Theodosius succeeded Jovinus as the magister equitum praesentalis at the court of the Emperor Valentinian I,[22] in which capacity he prosecuted another successful campaign (370/371) against the Alemanni.

[23][13] In 372 Theodosius was deployed to Illyricum and led an army against the Sarmatians; he appears to have secured a victory in battle and successfully brought the campaign to an end.

The reasons for this are not clear, but it is thought to have resulted from a factional power struggle in Italy after the sudden death of Emperor Valentinian in November 375.

He went on to establish an imperial dynasty of his own, making Count Theodosius the progenitor and patriarch of a line of Roman emperors and empresses.