The Sacrifice is an opera in three acts composed by James MacMillan with a libretto by the poet Michael Symmons Roberts based on the Branwen story of the Welsh mythology collection, the Mabinogion.
The world premiere took place on 22 September 2007 at the Donald Gordon Theatre of the Wales Millennium Centre, Cardiff.
The production was staged by Welsh National Opera, directed by Katie Mitchell and conducted by the composer.
The orchestra consists of 2 flutes, 2 piccolos, 2 oboes, cor anglais, 2 clarinets, bass clarinet, 2 bassoons, contrabassoon, 5 horns, 3 trumpets, 3 trombones, tuba, timpani (five drums in total) with a large percussion section for 3 players as well as 12 first violins, 10 second violins, 8 violas, 6 cellos, 4 double basses.
The third percussionist plays 2 chromatic octaves of crotales (with two double bass bows), 5 tuned gongs (one large, three medium and one small), güiro, vibraslap, 1 metal sheet, tenor drum, a pair of crash cymbals and tam-tam.