A book I read suggested that the Normans (once the initial few decades of destroying) did quite a good job, eliminating true slavery completely and making England very productive by the early 1200s.
Can't remember the name of it though. Was mostly about the lead up to Magna Carta. Had lots of funny quotes from the time, mostly along the lines of "the English are the best people in the world but they drink too much". Nothing has changed really...
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