- "Shame Archmaester Ch'Vyalthan wasn't a better writer."
Ch'Vyalthan, is an unseen character mentioned in the second season. He is deceased when the events of the series begin and is not expected to appear. He was an Archmaester of the Citadel and the author of the book An History of the Great Sieges of Westeros.
Tyrion Lannister refers to his book when preparing the defense of King's Landing. Varys criticizes him as an uninspired writer. Tyrion and Bronn debate how to correctly pronounce his name, but Varys offhandedly reveals the proper form: "sh(uh)-VY-al-thun".
In the Books
No mention of an Archmaester Ch'Vyalthan is made in the A Song of Ice and Fire novels.