Oresteia (Орестея in Cyrillic) is an opera in three parts, eight tableaux, with music by Sergei Taneyev, composed during 1887–1894.
Nikolai Rimsky-Korsakov wrote that soon after the premiere, the Mariinsky management made cuts to the opera, which angered Taneyev.
[1] The best-known excerpt from Oresteia is the entr'acte played before the second tableau of Part III, "The Temple of Apollo at Delphi".
This passage, as well as other themes from the opera, figured into one of Taneyev's other works, namely, his orchestral overture entitled Oresteia (1889).
Harlow Robinson has noted that the opera avoids dramatic treatment of the murders of Agamemnon, Cassandra, Clytemnestra and Aegisthus, depicting those events off-stage.