Expressions such as ‘author’, ‘work’, ‘text’ and ‘repertory’ are used constantly in writings about Italian opera; they stand for concepts that seem uncontroversial and unproblematic. However, these terms acquired the value we currently grant them only through a long process, one inextricably linked to the century-long formation of an Italian ‘operatic repertory’ between about 1750 and 1850. At the beginning of this period, a select number of literary texts received new musical clothing each time they were revived; by its end, the text of a successful opera could not be set to music again, because music and text were indissolubly linked in the audience's perception. There were exceptions, of course, and the process of change was gradual and differed according to genre: in the late eighteenth century some drammi giocosi had European careers that lasted as long as thirty years, much longer than the most successful drammi per musica. What is more, although we can speak of a ‘repertory’. with reference to the whole of Europe or to Italy, if we narrow the focusto a single city we may have to move into the nineteenth century to amass a body of works sufficiently large to merit the term. However, the fact that this process lasted for a century, far fromdiminishing its importance, is in one sense proof of its relevance. for an understanding of Italian opera that fully embraces its cultural, social and political context, ‘facts’ will indeed last as long as a century.