I have a piece on the Robber Barons in the current NRDT. I note that there were real robber barons of yore. In response, my medieval stuff gal writes:

You have been too kind to the robber barons. Sometimes they didn’t bother setting up spurious tollgates or “official” fees: Sidney Painter described English warriors who regularly changed allegiance during the twelfth-century struggle between Empress and Maude and King Stephen for the purpose of plundering lands owned by lords on both sides (with the worst damage suffered of course by the tenants, not the landlords). In the late 14th and early 15th centuries, Christine de Pisan complained about soldiers who “pillage and despoil the country like they do in France nowadays when in other countries they dare not do so. It is a great mischief and perversion of law when those who are intended for the defense of the people, pillage, rob, and so cruelly, that short of killing them or setting their houses on fire, their enemies could do no worse.” Just envision those scenes in “The Wind in the Lion” in which one army rushes through the marketplace, knocking over stalls and scattering the populace, and (much later) the army for the opposing side rescues the people–by rushing through the marketplace, knocking over stalls and scattering the populace. And then, of course, there are the Capitalists Pigs of the late 15th century, who discovered that collecting rents on tithes on the crops wasn’t half as profitable as getting in on the profits of the local metalworkers….