During the Roman period the area of modern Wales was at the extreme western edge of the known world. To the first Roman troops sent there, the people were a little-known race who fought fiercely to keep their independence. The Roman historian Tacitus described the fear of the soldiers when they arrived on the shores of Anglesey, the island of the druids. The druids were priests who accompanied the British warriors to battle. Their strange appearance made the Romans extremely nervous, and they were important in inciting rebellion.
Although the Romans massacred the druids and took the north of the region, the area was not garrisoned and more troops had to be brought in during the next 20 years. In the 3rd and early 4th centuries AD Roman control of Wales was strong but it always depended on vigilant defence. The emperors recognised the limits of their power so far from Rome and confined their efforts to the lowlands.

