Which opera has more acts, Der Zwerg or Billy Budd?
Der Zwerg Der Zwerg ("The Dwarf"), Op. 17, is an opera in one act by Austrian composer Alexander von Zemlinsky to a libretto by Georg Klaren, freely adapted from the short story "The Birthday of the Infanta" by Oscar Wilde.
Abu Hassan Abu Hassan is a comic opera in one act by Carl Maria von Weber to a German libretto by , based on a story in "One Thousand and One Nights". It was composed between 11 August 1810 and 12 January 1811 and has set numbers with recitative and spoken dialogue. The work is a Singspiel in the then popular Turkish style.