The Tumulus] This appears to have had considerable symbolic significance, see Suetonius, Claudius 1.3: the army erected a tumulus in honor of him, and every year, on a stated day, the army marched around it and the states of Gaul offered public sacrifice at it. Drusus was himself buried at Rome, but the tumulus represented his close connection with the army. The states of Gaul sacrificed here to express their loyalty to the house of Augustus.