The "Requiem" opens, after a few measures of prelude, with the chorus chanting the appeal for rest sotto voce, the effect being carried as pianissimo as possible until the basses, by an abrupt change of key, give out the theme of a fugue ("Te decet hymnus"), written in pure religious style. The introductory "Requiem" is repeated, and leads to the "Kyrie," the theme of which is stated by the tenor, and in turn taken up by the other soloists, the chorus shortly joining, a double sextet interwoven with it, and the whole closing pianissimo, as the "Requiem" opened. The second part, the "Dies Irae," is in strong contrast with the first, and is more broadly and dramatically worked up, and with freer accompaniment. The opening chorus is one of startling power. The tenors and basses open the number, immediately followed by the four parts announcing the Day of Wrath in high, sustained notes, while the second sopranos, altos, and tenors accompany them with immense sweeps of sound that rise and fall like the waves. There are nine numbers in this part which have been already specified, the most effective of them being the adagio trio ("Quid sum miser") for soprano, alto, and tenor, upon which Verdi has lavished his melodious inspiration. The trio is continually interwoven with the chorus shouting fortissimo the "Rex tremendae majestatis," until it takes another form in the prayer, "Recordare," a duet for soprano and alto in Verdi's best operatic vein. A very effective tenor solo, "Ingemisco," followed by a very solemn and majestic bass solo, "Confutatis," lead to the stirring measures of the Day of Wrath again, and close this part in an ensemble of immense power, both vocal and dramatic. The offertory ("Domine Jesu") is a quartet with three motives,--the first andante, the second allegro, and the third adagio in Gregorian form, the three themes being admirably worked up and accompanied. The "Sanctus" (the fourth part of the mass) is a very impressive allegro double chorus, followed by the "Agnus Dei," a duet for soprano and alto which is full of melodious inspiration, illustrated with charming instrumental color; it is the gem of the mass, and one of the happiest numbers Verdi has ever scored. The sixth part is the "Lux aeterna," a trio for alto, tenor, and bass which is very dramatic in setting; and this leads to the "Libera," the final division and the climax of the work. It is in its general effect a soprano obligato with chorus. After a monotone recitative and solo, the "Dies Irae" is repeated, likewise the "Requiem aeternam" (which forms the introduction of the mass), and closes with a fugue of majestic proportions that finally ends in the same pianissimo effect as characterizes the opening of the work.