The original manuscript of the score does not exist; two surviving copies from the 1650s show significant differences from each other, and each differs to some extent from the libretto. How much of the music is actually Monteverdi's, and how much the product of others, is a matter of dispute. None of the existing versions of the libretto, printed or manuscript, can be definitively tied to the first performance at the Teatro Santi Giovanni e Paolo, the precise date of which is unknown. Details of the original cast are few and largely speculative, and there is no record of the opera's initial public reception. Despite these uncertainties, the work is generally accepted as part of the Monteverdi operatic canon, his last and perhaps his greatest work.