The effects of that invasion are still with us as pointed out by Gregory Clark. Analysis of Norman Surnames and their predominance in elite families in Britain today, has shown that "Rich families stay rich and poor families stay poor, according to a new study that finds that English people whose ancestors were elite in the 1100s are still likely part of the upper crust today. The study echoes work in other countries that has found that social status budges little over generations, even in the face of massive social changes"