The four movements of the work are linked through the use of two contrasting ideas announced at the outset of the first movement: a sombre motif associated with death (Requiem aeternamdonaeisDomine) and a luminous one associated with salvation (et luxperpetualuceateis). The famous plainchant melody of the Dies irae, is utilised as a cuntusfirmus in the complex and dramatic evocation of the Day of Judgement that constitutes the second movement. It is followed by the DomineJesu, an anxious prayer for salvation, in which the motifs of light and darkness are juxtaposed. The work ends with the Lux aeterna, in which the luminous harmonies float around an unchanging falsetto note, symbolising the eternal light of salvation.