What mechanisms were available to musicians and scribes who sought to preserve popular compositions - or particular musical characteristics of compositions - once they became outdated or their performance context changed? What were the motivations for altering or transforming these pieces? How do different polyphonic settings of an older melody reveal different approaches to a musical past? These kinds of questions form a focus of the HERA Project: 'Sound Memories - Uses of the Past.' In this workshop we investigate some of these issues through three specific types of musical material: various realisations of 13th-century clausulae; a monophonic song of French origin and its different transformations in central European sources; different polyphonic settings of a late medieval song. Live performance within this workshop will enable direct comparison between different musical settings and provide a unique opportunity to assess these changes and to explore their sonic implications.