Europe 388: Battle of the Save
In 387 Magnus Maximus drove Valentinian II from Italy, thereby uniting most of the western Roman Empire under his rule. This provoked all-out war with the eastern emperor Theodosius, who marched west to decisively defeat Maximus on the Save river the following year.
387 Magnus Maximus invades Italy▲
In early 387 Magnus Maximus invaded northern Italy through the Alpine passes and seized Mediolanum (Milan). Caught by surprise, the 16-year-old Valentinian II and his mother Justina fled Aquileia with their court by sea to take refuge with Theodosius in Thessalonica. Their departure persuaded the Roman Senate to welcome Maximus, who soon extended his power across Italy and into western Illyricum.
388 Valentinian II’s Roman expedition▲
In late 387 Theodosius I agreed to cement his alliance with Valentinian II and his mother Justina by marrying Galla, Justina’s daughter to Valentinian I. The two emperors then agreed to retake Italy in 388, with Theodosius taking the overland route across Illyricum and Valentinian and Justina embarking from Thessalonica to reach Rome by sea, apparently believing that the Romans were disaffected with Magnus Maximus’ rule. In response Magnus Maximus sent Andragathius with a fleet to the Ionian Sea, but was unable to intercept Valentinian. Little else is known of this expedition except that Justina died later that year while Valentinian survived.
Jul 388 Battle of the Save▲
After suppressing some barbarian troops who had conspired with Magnus Maximus in Macedonia in early 388, Theodosius and his army—by now largely made up of Gothic troops and Hunnic auxiliaries—marched into the Diocese of Illyricum to confront Maximus himself. Pushing through Upper Pannonia, the four senior Theodosian generals—Timasius, Promotus, Arbogast, and Richomeres—crossed the Save (Sava) river near its junction with the Kupa at Siscia (Sisak, Croatia) in the face of heavy enemy opposition. Defeated, Maximus and his forces fled west to Aquileia and Poetovio.