The night before Don Giovanni's premiere in Prague, Mozart still had not written down the overture. Constanze later said she kept him awake with punch and stories while he wrote. His hostess, the soprano Josepha Duschek, once locked him in her garden pavilion until he wrote her an aria. Da Ponte, the librettist, was in town, and so was Casanova. The night is legend and memory; the words are imagined.