There were two great waves of immigration which swept over the south of Great Britain between the Christian Era and the Norman Conquest; and though they differed from each other in every other way, they were alike in this, that both of them left their mark very deeply upon the face of the country.

The Romans were bent on systematic colonisation, and on bringing this island within the circle of the Roman Empire, so that they could draw on its resources for supplies of food, and for recruiting their armies. The tribes of Jutes and Saxons and Angles, and their cousins, the Danes, settled piecemeal, here and there, according as they were attracted by one district or another and as the fortune of war turned them; the Romans introduced a high civilisation from Southern lands, while the heathen tribes seemed to hold nothing sacred and were ruthless in the destruction they wrought.

The Romans proceeded systematically, both in planting the towns and in laying out the fields round each centre. Cambridge, on the other side of the river, is a very good example of the sort of town they laid out. Lincoln and Winchester are very similar; all three lie on rising ground with a river at the foot, just outside the town. All three are oblong; and Cambridge was protected by a ditch and dyke of which we see remains in Mount Pleasant and in Chesterton Lane.