What is "perlesvaus"

Perlesvaus, also called Li Hauz Livres du Graal'' (The High History of the Holy Grail''), is an Old French Arthurian romance dating to the first decade of the 13th century. It purports to be a continuation of Chrétien de Troyes unfinished Perceval, the Story of the Grail, but it has been called the least canonical Arthurian tale because of its striking differences from other versions. It survives in three manuscripts, two fragments, and two 16th-century printings.