Some observations on the proposed Roman date for the Valu lui Traian

The persuasive redating by Hanson and Oltean (2012) of two of the Valu lui Traian linear fortifications of the Dobrogea in Romania to the Roman period requires an explanation of why the Romans should have constructed an internal land frontier in this region at a time when the Danube frontier was still being strongly garrisoned. The paper suggests possible contexts and functions for the Large Earthen Wall in the aftermath of the invasions of the Cotoboci in AD 171 or the Carpi in AD 214, and for the Stone Wall in the troubles of the late third century AD, possibly to limit the extent of small-scale encroachments, to which the river frontier itself was permeable in its lower reaches and Delta, and to keep them out of Thrace and the interior.