The aim of both Agricola and Hadrian was to convert Britain into a peaceful and self-governed Roman province. Their incentive was the love of an ideal. Each had a vision of stability and unity; but whereas Agricola's direct endeavour was to absorb and Romanize the whole island, Hadrian chose to consolidate rather than to extend. In helping the Britons south of the Wall line to keep out the raiding Caledonians, and encouraging them {4} to settle down, undisturbed, to peaceful agricultural and industrial pursuits, he hoped that in time the leaven of this higher ideal would spread north to the farthest limits of the island. And with this aim the Wall was built. In all ages the building of walls has marked a stage of advance in the evolution of human character, in so far as it has meant a progress from the offensive to the defensive position. In ancient Persia, the great reformer Zarathusthra condemned the raiding lives of the nomads, and held up the purer ideal of a peaceable and industrious community, dwelling within walls, and living on the fruit of their labour. Tradition says that he was slain by a resentful nomad on the steps of a temple, and thus he gave his life for his ideal. History repeats itself. Persia, China, Greece and Rome all built walls of brick or stone to keep out the enemy, and maintain the stability of their respective empires. Each had an ideal of unity to achieve, and sought in this way to promote it. In our own day, unity is still the ideal. Have we made a great advance over the methods of our predecessors? Rome had great qualities, great and good men; yet she fell. What did she lack? She has left us shining examples of strength, endurance, courage, justice and devotion to duty. Where did she fail? {5} She lacked just what we lack ourselves: the _true idea_ of unity, the true ideal of universal love, without which all other greatness "profiteth nothing." Are we just beginning to learn that the true "walls" which can alone preserve any nation or empire from destruction or decay, and which do indeed ensure its stability, are not walls of brick or stone, not armies, Dreadnoughts, aeroplanes nor submarines, but great moral and spiritual qualities, high aspirations, an ideal of unity which views the whole world as one, faced by one common enemy, and sees that, with the nation as with the individual, true greatness consists in humility and willingness to serve? "Violence shall no more be heard in thy land, wasting nor destruction within thy borders; but thou shalt call thy walls Salvation, and thy gates Praise." "Only the fashion of the soul remains." {6} CHAPTER II HISTORICAL In studying the Wall it is well to refresh our memory of Roman history wherever it relates to Britain, to sit in our mental "picture-house" as it were, and let scene after scene flit by us on the screen.