Who composed the opera Don Giovanni?

Mozart, in 1787, and the overture is famously supposed to have been written the night before the premiere, with his wife keeping him awake by telling him stories - the copyists reportedly had ink still wet on the parts. It is the sort of anecdote that has to be treated carefully and is at least contemporary.

It is a strange piece to classify. It is called a dramma giocoso, a jocular drama, and it opens with a murder and ends with a man dragged to hell by a statue - with comic servants and slapstick in between. Nineteenth-century audiences frequently had the final scene cut so it could end on the damnation rather than on the surviving characters cheerfully explaining the moral.

The librettist is the other story. Lorenzo Da Ponte wrote three of Mozart's greatest operas, was a Venetian priest expelled for adultery and keeping a brothel, later ran a grocery in Pennsylvania and a bookshop in New York, and ended as the first professor of Italian literature at Columbia. Casanova, who knew him, was in Prague during rehearsals, and notes in his papers suggest he had a hand in revising a scene - a man whose name became the word for a seducer helping to write the opera about one.