Half a century ago, few but scholars knew or cared that Don Carlo was written in French (not Italian), in five acts (not four), that the action took place in France as well as Spain, and that the proper title is Don Carlos. And let’s not even get started on all the revisions. The Metropolitan Opera has been presenting an unusually comprehensive five-act edition for decades, but is only now coming around to French. This season’s new production marks the British director David McVicar’s 11th outing with the company; expect spectacle delivered with clarity, nuance, and gravitas. Matthew Polenzani, a versatile lyric tenor of the first rank, stars as Carlos, a king’s son with more than a touch of Hamlet in him. Nézet-Séguin conducts. —Matthew Gurewitsch