The siege demonstrated Julian's vulnerability in Gaul and exposed Marcellus's failure to relieve a Roman commander under attack.
Key Facts
- Year
- 356 AD
- Duration of siege
- Approximately one month
- Outcome
- Roman victory; Germanic forces withdrew
- Roman commander
- Julian the Apostate (Caesar)
- Dereliction of duty
- Marcellus, master of the horse, failed to send relief
Location
Cause → Event → Consequence
In 356, Julian the Apostate wintered at Senonae in Gaul after leaving Cologne. Desertions among his German federated troops left his garrison under-strength, and hostile Germanic warbands, learning of this weakness, seized the opportunity to attack the town.
Germanic forces surrounded Senonae and blockaded Julian inside its walls for approximately one month. Lacking the advanced siegecraft needed to breach the defenses, they could only prevent Julian from leaving the town. Marcellus, master of the horse, stationed nearby, failed to send any reinforcements despite the danger to the Caesar.
After about a month the Germanic forces abandoned the siege and withdrew. Marcellus's failure to relieve Julian was regarded as a serious dereliction of duty and a shameful episode, reflecting poorly on Roman military discipline and the treatment of a commander of Julian's rank.
Belligerents & Mobilization Analysis
Side A
1 belligerent
Julian the Apostate, Marcellus (master of the horse, non-participant).
Side B
1 belligerent