Suetonius in his work “Lives of the Caesars” devoted to successive rulers up to the times of Domitian (81-96 CE) mentions many amazing stories from wars that are intended to interest the reader and emphasize the heroism of the Romans.
Suetonius tells how it was during the naval battle of Massilia (present-day Marseille, in the south of France) in 49 BCE soldier Gaius Acilius when seized the rear of the enemy ship, and his arm was cut off. The Roman, however, did not give up, jumped on the enemy unit and successfully pushed the rivals away with the tumour on the scutum shield. Acilius was to follow the example of the Greek soldier Cynegirus, who died in a similar situation after having his hand cut by an enemy axe (Herodotus, Histories, VI.114). It seems that the story was meant to emphasize the ferocity of the Roman soldiers.