Columbia subject headings:
Harvard subject headings:
History in opera--Congresses.
Opera--Italy--18th century--Congresses.
Opera--Italy--19th century--Congresses.
Princeton subject headings:
Ariosto, Lodovico, 1474-1533--Adaptations.
Characters and characteristics in opera.
History in opera.
Opera--Italy.
Operas--Literary themes, motives.
Tasso, Torquato, 1544-1595--Adaptations.