Topos of Barbarians Lacking Siege Engines

[Sean Manning]

By the first century BCE, there was a Roman topos that barbarians lacked siege machines. Like most topoi, this had some rough-and-ready truth in the present and an ugly psychological root: sure, people like the Caledonians or the Suebi could not build catapults and battering rams like the Romans could, but people like Diodorus did not want to admit that until the 5th century BCE it was only people from Syria, the Levant, and Carthage who knew how to take a walled city , or that Phoenician siege engineers were still respected in the 4th century BCE. It was applied to the Ottomans in the 15th and 16th century by sore losers.

Has anyone gathered passages which use this topos such as Caesar, Commentarii de Bello Gallico, V.42.1-3 or Tacitus, Annals, 12.45? I think Procopius has fun with this.