Giuseppe Verdi’s Don Carlo, which premiered in 1867 in Paris as Don Carlos, exists in several versions, and, depending on which is performed, is either his longest or one of his longest operas. Although the first performance was in French, Nicholas Hytner’s 2008 production for the Royal Opera House employs the Modena version of 1886, which is one of several to utilise an Italian libretto. Don Carlo ; © ROH, Catherine Ashmore Don Carlo ; © ROH, Catherine...