 Although many Roman towns in the later empire built stone defences (such as walls and a gatehouse identified at Cunetio, near Marlborough ten miles to the south) this defensive work did not occur at Durocornovium.It may be this was impossible on the marshy ground existing at the time, or simply that it was economically not viable, and it is notable that the hill fort at Liddington immediately to the south was re-occupied in the 3rd century.It was not for shortage of stone