The history of Britain’s population is a familiar story to many. It tells of an ancient people (retrospectively dubbed the Celts) and subsequent invasion and settlement by the Romans, Anglo-Saxons, Normans and Vikings. And many people today still identify strongly with one or another of these groups.
However, historical records have their weaknesses. For example, it’s very difficult to know to what extent an invasion amounted to mass settlement replacing an existing population, and how much it was a small elite converting that existing population to a new way of life.