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
Merlyn explains how, when he was young, there was a general idea that it was wrong to fight in wars. There is only one really good reason for fighting: if the other side starts it. There is no excuse, Merlyn emphasizes, for starting a war.
Merlyn's peculiar experience of time allows the reader to compare medieval interpretations of war with our own contemporary ones. This comparison will arise again and again.