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
Still, there is no news of Lancelot. Rumors circulate of Lancelot unhorsed, defeated, dead. Finally, one wet and miserable day, Lancelot comes back, leading a white mare out of the rainstorm. The whole court gathers but Arthur quickly ushers them away. Two hours later, Uncle Dap presents himself to the King and informs him that the Holy Grail has been found by Galahad, Percival, and Bors who are with it now, carrying it to Babylon; Bors will eventually return home, the others will not.
The moment in which Arthur learns the Holy Grail has been found is anti-climatic: he is told by Uncle Dap, rather than Lancelot himself, and little seems to be changed by this news. Indeed, the knights who did find it will never return, suggesting that the goodness and purity that Arthur hoped to instill in his knight's through the quest is actually impossible for normal people living in the real world to attain. In some ways, the quest is powerful only for so long as it is incomplete, because in its completion the ideal that motivated is revealed as an illusion.