Unfortunately you don't need to study history or do the hard slog of studying at University to obtain knowledge about the past, human migrations and genetics, you just turn on your computer. In the past this knowledge would be called gossip and old wives tales. It is okay for the Roman Empire to be in Britain for some hundreds of years and leave just foundations, walls, the city of Bath but no genetics of Roman citizens in the current British population. Then there is Iberia, and it was one big fuck fest, Romans, Arabs, North Africans, Black Africans and Jews. In some countries, race is a big agenda especially the dark African groups, and that distorts their understanding of the past, history, movement of people and the type of people.