The Invasion and Conquest of Britain
In AD43 the Emperor Claudius ordered a Roman army about 40,000 strong to cross the Channel and invade Britain. Oppoisition was rapidly dealt with and the Celtic tribes of the south and east incorporated into the empire and formed into a province.
Following the death of Nero in AD68 and the ensuing Civil War, the new Emperor Vespasian ordered a general advance, presumably with the intention of completing the conquest of the island. His generals subdued the Welsh tribes, incorporated the former friendly kingdom of the Brigantes in northern England into the province, and pushed on northwards to defeat the Caledonians in the battle of Mons Graupius, the location of which is, unfortunately, not known but probably lay in north-east Scotland.
Britain, the Roman historian Tacitus triumphantly said, was conquered, but, he went on to say, was immediately relinquished. The reason for this was not due to events in the island, but far away on the Lower Danube. The defeat of Roman armies at the hands of Dacians, who occupied modern Transylvania, led to reinforcements being dispatched from Britain. This resulted in the abandonment of nearly all forts north of the Tyne-Solway isthmus, where thirty years later the Emperor Hadrian ordered the construction of the great wall which still bears his name.