Sir Gawain and the Green Knight captures the beauty and the brutality of the medieval world in rich detail. The narrator describes the opulence of court life and the deadly violence that courtiers considered games. These rich descriptions that permeate the poem place the reader firmly in the 14th century. However "medieval" the poem may be, many of its underlying themes are reflections on ancient ideas. Sir Gawain and the Green Knight can be read as a medieval treatise on knighthood, but it can also be interpreted as treatise on the ancient Greek notion of “right governance” as first described by Aristotle.

The description of Camelot in section 6 of Fit 1 is reminiscent of Aristotle’s description of the just and well-ordered state he describes in Politics. The courtiers of Camelot and the Knights of the Round Table are “seemly” or decorous, meaning they conduct themselves in a rational, moderate manner, even in celebration. Aristotle describes the “right governance” of the ideal polis in the same way. The citizens of this polis conduct their public affairs with civility and moderation. Their leaders are paragons of “right governance” in their administration of the law and their own souls. Arthur himself is described as “comely,” or attractive and well-ordered, but the word also connotes rightness and correctness of mind. Aristotle’s insists that the ideal polis be led by men who follow right reason and make correct decisions based on rationality. The Green Knight’s appearance in the hall disrupts that rational and decorous behavior, so Gawain’s quest can be read as the citizen of the polis fulfilling his duty to manage state affairs and threats to the state’s survival with vigorous action.

In contrast to Camelot, the court of Bertliak is a polis ruled by passion, not reason. Bertilak’s court under the influence of Morgana, is focused on pride, the desire for revenge, and lust, all characteristics that Aristotle identified as hallmarks of tyrannies. In section 36 of Fit 3, Bertilak himself is described as “powerful” and “stupendous,” suggesting a man who lives by force, not reason. He is “fierce,” not comely like Arthur. In Politics, Aristotle repeatedly warns against the attractive but corrupting glamour of states ruled by such passions. Bertilak “seemed in good sooth a suitable man / To be a prince of people with companions of mettle” (emphasis mine), suggesting that his appearance may be attractive, but his true nature has been perverted by Morgana’s malevolence. Bertilak’s courtiers are men of “mettle,” or heart, unlike Arthur’s “seemly,” “decourous,” rational companions.

Sir Gawain and the Green Knight can be understood as a treatise on leadership. Citrizens of communities, like Gawain, have obligations to defend their polis and live according to the dictates or reason and decorum, but it is the leader of the polis who has the most reposniorepsonsibilityy. His governance, right or otherwikse, will determine if the citizens of the polis enjoy peacful, "seemly" lives. Arthur-- and ultimately Christ-- is the ideal or paragon of the reasonable leader, As with all Medieval literature, the ancient is subsumed in the Christian.