Question:  The House of Atreus Act I, released in 1999 is the first part of a metal opera inspired by the  only extant example of an ancient Greek theatre trilogy which won first prize at what festival?
Sentence (from "Ichneutae"): With more than four hundred lines surviving in their entirety or in part, the "Ichneutae" is now the best preserved ancient satyr play after Euripides' "Cyclops", the only fully extant example of the genre.
Relevant evidence: No