Avalon is a legendary island featured in Arthurian legend. It first appeared in Historia Regum Brittaniae (History of the Kings of Britain) by Geoffrey of Monmouth. It was the place where Excalibur was forged and the last resting place of Arthur after Camlann.
In Arthurian legend, after Arthur fell at Camlann, he was taken by nine sisters (chief of whom was Morgana, to Avalon. There he would rest until he was required to rise and save his people from disaster.
Geoffrey of Monmouth refers to it as Insula Avallonis in Historia Regum Brittaniae. In Vita Merlini (The Life of Merlin), it is called Insula Pomorum (Isle of fruit trees). Avalon is likely derived from the Old Welsh "aball" (apple), which evolved into Middle Welsh "avall" and Modern Welsh "afall". It is related to the Breton "aval" (pl. "avaloù") meaning apple. The Celtic root, ancestor of the Gaulish root *aballo-, stem of Avallon in Burgundy, is descended from *abal-, the Proto-Indo-European root from which the English "apple" is descended.
Avalon is associated with many sites, such as Sicily, the afore-mentioned Avallon in Burgundy,as well as Glastonbury. The Glastonbury connection stems from 1190, when, the tombs of Arthur and Guinevere were reportedly found there. Glastonbury claims to have been an island because, in pre-Saxon England, it was surrounded by marshland.