There is no doubt that a handful of compositions from the seventeenth century have become part of the modern ‘classical’ repertory. If they are not quite standard concert war-horses owing to their ‘unorthodox’ scoring, they are nevertheless recognised as ‘great works’ of early music: Monteverdi’s 1610 Vespers and Purcell’s Dido and Aeneas perhaps come most readily to mind. However, the vast majority of this century’s music is still seen as the province of specialist performers, somehow separate from the musical mainstream. It is not the brief of this chapter – or indeed of this book as a whole – to function as a comprehensive critique of current musical values and concert practices, yet some awareness of our own assumptions and prejudices is surely vital in any historical study whatsoever. The question that thus arises is whether musical compositions of the seventeenth century are appropriately described as ‘works’. And this leads to a whole string of further questions. Did seventeenth-century composers believe they were writing works? Did those who received these compositions believe them to be works? Or are certain pieces retroactively defined as works – as may be the case with those familiar pieces by Monteverdi and Purcell? And are these defined as works because of qualities latent within them and common to great works of all ages, or is it that they just contain elements that might be seen as conforming to a historically conditioned ideology of what a work should be?