Magnus Maximus
The peace with Magnus Maximus was broken in 386 or 387, when he invaded Italy from the west. Valentinian, escaped with Justina, reaching Thessalonica (Thessaloniki) in the eastern empire in the summer or autumn of 387, appealing to Theodosius for aid. Magnus Maximus reached Milan to begin his consulship of 388, where he was welcomed by Symmachus. Valentinian II's sister Galla was then married to the eastern "augustus" at Thessalonica in late autumn. Justina, widow of Valentinian I and mother of Valentinian II, died in summer 388. In June, the meeting of Christians deemed heretics was banned. In summer 388, Italy was recovered for Valentinian from Magnus Maximus, whom Theodosius defeated at the Battle of Poetovio and eventually executed at Aquileia on 28 August.