A Distant Mirror by Barbara Tuchman
Chivalry, the dominant political idea of the ruling class, left as great a gap between ideal and practice as religion. The ideal was a vision of order maintained by the warrior class and formulated in the image of the Round Table, nature’s perfect shape. King Arthur’s knights adventured for the right against dragons, enchanters, and wicked men, establishing order in a wild world. So their living counterparts were supposed, in theory, to serve as defenders of the Faith, upholders of justice, champions of the oppressed. In practice, they were themselves the oppressors, and by the 14th century the violence and lawlessness of men of the sword had become a major agency of disorder.
One of the many, many reasons why arming all the privileged people with guns so that they can protect us with their White Knightiness is a really bad idea.