LitCharts assigns a color and icon to each theme in The Once and Future King, which you can use to track the themes throughout the work.
Chivalry, Satire & Medieval Life
Fate (Time)
Quest and The Holy Grail
Might vs. Right
War
Summary
Analysis
Lancelot and Guenever, now aged lovers, are sitting in the window of her solar, looking out over Arthur's medieval England. The land is unrecognizable to what it was before Arthur's rule. Before, Barons hung and slaughtered people at their will, cottagers bared their doors each night in fear, churches were used as forts and people died daily from diseases such as the black death. Now, there are libraries and universities, beautiful architecture, justice and law.
There is peace in the realm now. What we witness from the lovers' eyes is a reformed England. White describes a kingdom of law, justice, intellect, and civilization. White's description is long and detailed and simply communicates how enlightened England has become.
Active
Themes
But, perhaps most importantly, there was a control over Might. During this period, the Catholic Church could even impose a peace on fighting—which was called The Truce of God and lasted Wednesday to Monday and during the whole of Advent and Lent.
Moreover, Arthur has not simply imposed enlightenment, but a control over Might. In this, Arthur seeks to achieve some kind of valuation of humanity above all other things.