Musicologist Ellen T. Harris wrote an authoritative book on this opera three decades ago – a book she has had to completely revise and reissue based on all the info scholars have uncovered over those years. Yet “we know even less [now] than we did then, or at least less than we had imagined. We can no longer say with certainty in what year the opera was written, where it had its premiere, who performed it or even what the original score contained.” In this essay for the Times, Harris explains what it turns out that we’d wrongly assumed and what we’ve learned that upended those assumptions.