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
In Lancelot's castle, men sit around a bright fire. They are confused as to why the siege was lifted so quickly. They wonder if the King is ill, or if there has been a revolt in England. Lancelot enters suddenly, shouting for his men and carrying a letter. The letter has come ashore from England but was delayed by a storm. It was written by Gawaine—the first letter he had written in year. The letters explains Mordred's treason, about Guenever barricaded in the tower, and that the King has landed at Dover and won the first battle against Mordred. The letter is from Gawaine, but Gawaine says that by the time the letter reaches Lancelot he will be dead. He writes to give his forgiveness to Lancelot and to ask his forgiveness for his own siege. He writes that he is close to death from his wounds in battle. He urges Lancelot to travel with haste to help the King.
The letter Gawaine writes to Lancelot is deeply poignant. It exposes a side to Gawaine we have not previously seen. Throughout the novel, he is a vulgar, barbaric knight who cannot truly grasp Arthur's concepts of good and justice. But his letter reveals a somewhat childlike understanding of things and a sensitive and truly repentant knight.