The Marcomanni invaded Italy in 166 AD, razed the city of Oderzo and besieged the frontier fortress of Aquileia; thus starting the Marcomannic War which raged until 180 AD and the death of Marcus Aurelius. The Praetorian Prefect Titus Furius Victorinus was killed and his legions destroyed trying to relieve the siege. The diorama shows the siege of Aquileia by the Marcomanni, a confederation of German tribes. The Romans sally from the gate in an attempt to destroy the siege tower assaulting the wall. The artillery tower Ballista is firing on the siege tower while being attacked by a battering ram. 
