 It had a line of walls built to defend it from the attacks of the Alamanni, who nevertheless destroyed it in 259-260.The name "Rottenburg" is thought to derive from a Germanic root that is also present in the English word "rotten", in an older meaning of "destroyed".According to this hypothesis, the town would have received its name when, in the early Middle Ages, Alemannic people founded their settlement in the vicinity of the ruins of Roman Sumelocenna.