Source analysis has long proven a productive tool in Shakespeare studies, given the breadth, abundance and variety of narrative traditions that Shakespeare demonstrably borrowed from and adapted. In addition to the insight that the study of identified sources can provide into the processes of narrative construction and adaptation in his plays, this approach also sheds valuable broader light on the dynamic literary and cultural mosaics of early modern England and Europe more widely. This, in turn, informs scholarly understanding of what types of stories or texts were known, being actively transmitted and reshaped, and resonating with contemporary readerships and audiences. Additionally, identifying and understanding Shakespeare’s sources can often usefully illuminate the chronological development and evolution of individual narrative traditions to which those sources belong, traditions which variously extend back to biblical, classical and medieval roots.1 Source analysis does have clear and obvious limitations, however. For one thing, the scale of influence on any text or author inevitably varies from source to source, meaning that filiation cannot always be posited conclusively. For another, Shakespeare is recognized to have collaborated actively with other playwrights, which complicates questions of direct influence.2 For a third, not all of Shakespeare’s (or his co-authors’) literary sources have survived. Then there is also the substantial matter of oral sources and traditions, of which little can be definitively known, barring the fortuitous survival of sufficient auxiliary evidence such as analogues. The murky uncertainties which arise from such issues are evident in the long debate over the nature of Hamlet’s relationship with the putative ‘ur-Hamlet’, which serves to exemplify both the accepted value of source identification and the extent of its limits.