What Simetrical is trying to say, is that the 'barbarians' were every bit as culturally and technically advanced as the so called 'civilised' states. Although they didn't leave the lasting infrastructure and architecture the Romans and such left behind after their demise, they also had highly developed societies and had their own technical brilliances (such as metalworking).

Hell, it should say something to you that Rome, for all its civilisation and supposed advanced nature, never truly managed to pacify its barbarian opponents. Got a damn good drubbing when they started sniffing at northern Europe beyond Gaul.