Dragons, Wyrms, and Wyverns: Their Unnatural History
From A Wiki of Ice and Fire
Dragons, Wyrms, and Wyverns: Their Unnatural History is an important I corpus about dragons by Septon Barth, the Hand of the King of Jaehaerys I. He was considered more of a sorcerer than a Septon by his enemies. Because of this copies of this book were burnt during the reign of Baelor I and it is hard to find.[1] It claimed that dragons were neither female nor male.[2]
In the book Septon Barth also dispelled the myth that a dragon could be slain by attacking down its gullet, he quoted in the book...
"Death comes out of a dragon's mouth, but death does not go in that way".[3]