Come to think of it, one could easily draw parallels between the Harkonnens and the historical Mamelukes, who were, essentially, warrior slaves, yet the position of a Mameluke was so prestigious that people would sometimes sell themselves into slavery to get a chance to become part of the Mameluke elite. Fh mentions that even though the Harkonnen populace was confined to a slave-like existence, serving in the Baron's military was the most prestigious position one could get, making Harkonnen soldiers the elite of their society.Underlying all of this was what the Harkonnens had left behind -- genetic lines tracing far away into the dawn times of Greek and Pathan and Mameluke, shadows of ancient history that few outside of professional historians or those trained by the Bene Gesserit could even name.
I believe it is also quite possible to draw similar parallels between the Mamelukes and the Sardaukar...