Avilion is a fantasy novel by British author Robert Holdstock. It was published in the United Kingdom on July 16, 2009. It is his first Ryhope wood novel since Gate of Ivory, Gate of Horn was published in 1997. Avilion is Tennyson's term for Avalon in Idylls of the King. Avilion is described by Tennyson as an island valley with ideal weather and fertile land.The novel Mythago Wood introduces tropes, terminology and a backstory that are built upon in Avilion.