On the death of Valentinian (17th of November 375) the troops in Pannonia proclaimed his infant son (by a second wife Justina) emperor under the title of Valentinian II.
Richter, Das westriimische Reich, besonders unter den Kaisern Gratian, Valentinian II.
This victory was followed by the murder of Maximus and his son Victor, after whose death Theodosius conferred upon Valentinian II.
The pagan party was led by Quintus Aurelius Symmachus, consul in 391, who presented to Valentinian II.
His complete success, which resulted in the destruction of Maximus and his sons and the pacification of Gaul, led Theodosius to appoint him chief minister for his young brother-in-law Valentinian II.