Eugenius, after being installed as Western Emperor following the death of the teenaged emperor Valentiian II, changes the imperial administrators.

When Theodosius had left the western half of the empire to Valentinian, he had put his own men in the highest civil offices, to keep a strong grasp on the whole empire.

Eugenius replaces these administrators with others loyal to himself, coming from the senatorial class.

Nicomachus Flavianus the Elder becomes Praetorian Prefect of Italy, his son Nicomachus Flavianus the Younger receives the title of Prefect of Rome, while the new praefectus annonae is Numerius Proiectus.

Eugenius is nominally a Christian, and therefore is reluctant to accept a program of imperial support to Polytheism.

His men, however, persuade Eugenius to use public money to fund 'Pagan' projects, such as the rededication of the Temple of Venus and Rome and the restoration of the Altar of Victory within the Curia (removed by Emperor Gratian).

This religious policy creates tension with Theodosius and …

…the powerful and influential Bishop Ambrose, who leaves his see in Milan when the imperial court of Eugenius arrives.

Eugenius, when elected emperor in the West, had sent ambassadors to Theodosius's court, asking for recognition of his election.

Theodosius had received them, but started to gather troops to defeat Eugenius.

Theodosius leaves no further doubts as to his position when in January 393 he elevates his nine-year-old son Honorius to Augustus of the West and thereby demonstrates that he will no longer tolerate any emperor other than himself and his sons.

The now inevitable struggle for power is thus at the same time a struggle that will decide whether other religions will again be tolerated within the empire alongside Christianity.

Because Theodosius still refrains from military action, his enemies occupy Italy in the spring of 393.

Led by Roman prefect Nicomachus Flavianus, the forces striving to preserve the old cults gather around Eugenius.