DIES IRAE (Lat., "day of wrath"), the opening words of a Latin hymn on the Last Judgment, ascribed to Thomas of Celano (c. 125o) and forming part of the Office for the Dead and Requiem Mass; in music, the traditional plain-song melody to which the words are sung and settings in general of this portion of the Mass. Among famous examples of the latter may be mentioned those of Mozart, Cherubini, Berlioz and Verdi.