Late Roman Empire, Valentinian-Theodosian Dynasty (364-455): 72*Arcadius, 73*Magnus Maximus, 74*Flavius Victor; Theodosius-I/Magnus Maximus’ Civil War, [11/12]

72*ARCADIUS (30/31; r.383-408) (East)

73*MAGNUS MAXIMUS (u; c.53; r.384-388) (W)

74*FLAVIUS VICTOR (r.384-388) (W)

In January 383, Theodosius proclaimed his elder son ⁴²Flavius Arcadius co-ruler for the Eastern Empire. In the spring ⁴³Flavius Magnus Maximus was proclaimed by his troops as augustus. He crossed to Gaul and in early summer Gratian left Milan to confront him. Gratian’s army defected to Maximus near Lutetia (=Paris). On 25 August, Maximus’ magister equitum Andragathius (fl.383-388) killed Gratian near Lugdunum (=Lyons). In 384 Maximus and Theodosius agreed that Valentinian II was to remain as the ruler of the Italy prefecture, while Maximus and his son ⁴⁴Flavius Victor became co-rulers of the Gaul prefecture.

  In summer 386, the Greuthungi, led by Odotheus, and their allies appeared on the left (north) bank of the lower Danube. When they tried to force their way across the river the magister peditum per Thracias ⁴⁵Flavius Promotus (fl.386-391) inflicted a crushing defeat on them

In 387 Theodosius and Shapur III (r.383-388) signed the Peace of Acilisene, by which the Persians formally ceded to Rome the western fifth of Greater Armenia, ruled by the pro-Roman king Arsaces III (r.378-387).

Theodosius-I/Magnus Maximus’ Civil War (387-388) [11/12]

Battle: Sava River	Croatia	Theodosius-I/Magnus Maximus	388
Battle: Poetovium	Slovenia	Theodosius-I/Marcellinus	388

In summer 386, Maximus and his army invaded northern Italy. The twelve-year-old emperor Valentinian II fled from the imperial court at Mediolanum (=Milan) and travelled to Thessalonica. When Magnus Maximus invaded Italy in 387, he left his son ⁴⁴Flavius Victor (fl.384-388) in Trier under the care of his magistri militum Quintinus (fl.387-388) and Nannienus (fl.370-388).

In 388 Theodosius assembled an army composed largely of non-Roman soldiers, which included formations of Gothic, Alani and Vandal allies. His commanders on this campaign were the magister equitum ⁴⁶Flavius Promotus, the magister peditum ⁴⁷Flavius Timasius (fl.378-396), and two Frankish commanders, the magister militum per Orientem ³⁹Flavius Richomeres, and his nephew, the Western magister peditum ⁴⁶Flavius Arbogast (fl.380-394).

Theodosius split his forces into three groups that advanced north from Thessalonica up the Vardar and Margus rivers through Moesia Superior to Singidunum (=Belgrade). The southern army confronted Maximus’ force near the town of Siscia (=Sisak), located at the confluences of the Savus (=Sava), Colapis (=Kupa) and Oder rivers. Theodosius’ Hunnic cavalry forded the river, closely followed by the mounted archers of the Alani and Goths. After the enemy cavalry had been driven off, the bowmen concentrated their assault on the fleeing infantry. The battle was over in a short time.

The northern group then fought and defeated a stronger army led by Marcellinus, the brother of Maximus, at Poetovium (=Ptuj) on the Drava. Theodosius pressed on to the Julian Alps into the northern plain of Italy and advanced on Aquileia, where Maximus had taken refuge. The city soon fell and Maximus was taken prisoner and killed. Maximus’ son Victor was captured in Gaul and executed. The Western Empire was now united under the rule of Valentinian II, but Theodosius was effectively in overall control of the Empire.

Around this time the Frankish subreguli (petty kings) Marcomer, Sunno and Genobaud crossed the Rhine near Cologne and penetrated at least as far as the Ardennes (France-Luxembourg-Belgium-Germany), where they were savaged by Nannienus and Quintinus, and driven back. Quintinus attempted a counterattack over the Rhine near Novaesium (=Neuss), but was badly beaten on difficult ground. In 389 Arbogast made an agreement with Marcomer and Sunno. 

In 390 reports from Thessalonica reached Theodosius that a mob had lynched Butheric, the Gothic magister militum in Illyricum, in anger over the imprisonment of a popular charioteer. In a fit of fury over this perceived defiance of his authority, Theodosius ordered his troops to carry out a punishment, which intentionally or not, ended in a massacre of the citizens of Thessalonica to avenge the death of Butheric. 

Over seven thousand people were slain. Ambrose (c.57; r.374-397), Bishop of Milan, was appalled and he refused to admit Theodosius to his cathedral until he showed repentance. Eight months passed before the emperor abased himself before the altar in Milan. This is the first victory of the authority of the Church over that of the State.

In February 391, following his reconciliation with the Church, Theodosius issued an edict from Milan banning traditional Roman religious sacrifices and rituals, a law with huge implications for non-Christian Romans.