Hadrian's Wall stretches across the isle of Britain, crossing some of the most dramatic and harsh terrain in Britannia and cutting the island in half. Hadrian was concerned with consolidating and defining the Empire he received in AD 117, unlike his predecessor Trajan, who had continued the policy of unbridled expansion of Rome's borders. The building of the wall defined the limits of the Roman Empire. Britannia was one of the newest provinces in the Empire, conquered for less than a century. The island was not completely subjugated by Rome and rebellions were common. Hadrian saw the wall as an opportunity not only to solve the problem of northern incursions, but also to send a message to those living below the wall in the province. Hadrian intended that the province would become part of the Empire and embrace the Roman culture that the Britons up to this point had avoided accepting.
By building the wall, Hadrian created not only a defensive line that separated the barbarians beyond it from the civilized, but also created a symbol. The wall symbolized the disassociation of the province of Britannia from the northern portion of the island. It showed the permanence of the Romans in Britannia and the power of the Roman state. Hadrian wanted the Britons to see themselves as Romans, not Britons. It was his hope that the wall would be not only a physical barrier but also a psychological barrier for those in the south as well as the north. The wall became part of a larger strategy of symbols used by Hadrian, including coins he produced commemorating the province and the military stationed in it as well as building projects through out the Empire.http://historyoftheancientworld.com/2012/08/hadrians-wall-romanization-on-romes-northern-frontier/