The idea of continuation in medieval literature is a familiar one - but difficult to define precisely. Despite the existence of important texts which are commonly referred to as continuations, such as Le Roman de la Rose , Le Chevalier de la Charrette and, of course, the Perceval Continuations , the mechanics and processes involved in actually producing a continuation have found themselves indistinguishable from those associated with other forms of medieval réécriture . The Perceval Continuations (composed c.1200-1230) constitute a vast body of material which incorporates four separately-authored continuations.