Wolfgang Amadeus Mozart's Requiem in D minor (K. 626) is considered by many to be one of the greatest works of classical music. It was composed in 1791, supposedly as Mozart lay on his deathbed, but Mozart was unable to complete the work before his death.

Popular legend says that an unknown messenger commissioned the Requiem from Mozart, but it's now believed by many scholars that the patron was Franz Anton Leitgeb, a Vienna music lover who gave concerts at his home. The Requiem was commissioned for Leitgeb's late wife, but Mozart was fond of telling his wife that he was composing the Requiem for himself (he also enjoyed imagining that he was being poisoned).

At his death, Mozart had finished only two sections of the Requiem, but the notes he left allowed two of his students to complete it.

Most people know of the Requiem because of the film "Amadeus", which used large portions of the piece to masterful effect. Because of its prominence in the movie, the Requiem may now be Mozart's most recognizable work.

Requiem

Requiem

Requiem aeternam dona eis, Domine,
et lux perpetua luceat eis.
Te decet hymnus, Deus, in Sion,
et tibi reddetur votum in Jerusalem.
Exaudi orationem meam,
ad te omnis caro veniet.
Requiem aeternam dona eis, Dimine,
et lux perpetua luceat eis.

Kyrie

Kyrie

Kyrie eleison.
Christe eleison.
Kyrie eleison.

Sequence

Dies irae

Dies irae, dies illa
Solvet saeclum in favilla,
Teste David cum Sibylla.

Quantus tremor est futurus
Quando judex est venturus
Cuncta stricte discussurus.

Tuba mirum

Tuba mirum spargens sonum
Per sepulcra regionum
Coget omnes ante thronum.

Mors stupebit et natura
Cum resurget creatura
Judicanti responsura.

Liber scriptus proferetur
In quo totum continetur,
Unde mundus judicetur.

Judex ergo cum sedebit
Quidquid latet apparebit,
Nil inultum remanebit.

Quid sum miser tunc dicturus,
Quem patronum rogaturus,
Cum vix justus sit securus?

Rex tremedae

Rex tremendae majestatis,
Qui salvandos salvas gratis,
Salve me, fons pietatis.

Recordare

Recordare, Jesu pie,
Quod sum causa tuae viae,
Ne me perdas illa die.

Quaerens me sedisti lassus,
Redemisti crucem passus,
Tantus labor non sit cassus.

Juste judex ultionis
Donum fac remissionis
Ante diem rationis.

Ingemisco tamquam reus,
Culpa rubet vultus meus,
Supplicanti parce, Deus.

Qui Mariam absolvisti
Et latronem exaudisti,
Mihi quoque spem dedisti.

Preces meae non sunt dignae,
Sed tu bonus fac benigne,
Ne perenni cremer igne.

Inter oves locum praesta,
Et ab haedis me sequestra,
Statuens in parte dextra.

Confutatis

Confutatis maledictis
Flammis acribus addictis,
Voca me cum benedictis.

Oro supplex et acclinis,
Cor contritum quasi cinis,
Gere curam mei finis.

Lacrimosa

Lacrimosa dies illa
Qua resurget ex favilla
Judicandus homo reus.
Huic ergo parce, Deus,
Pie Jesu Domine,
Dona eis requiem.

Offertory

Domine Jesu

Domine, Jesu Christe, Rex gloriae,
libera animas omnium fidelium
defunctorum
de poenis inferni, et de profundo lacu:
libera eas de ore leonis,
ne absorbeat eas tartarus, ne cadant
in obscurum,
sed signifer sanctus Michael
retraesentet eas in lucem sanctam,
quam olim Abrahae promisisti
et semini ejus.

Domine Hostias

Hostias et preces, tibi, Domine,
laudis offerimus;
tu suscipe pro animabus illis,
quarum hodie memoriam facimus:
fac eas, Domine, de morte transire ad
vitam,
quam olim Abrahae promisisti
et semini ejus.

Sanctus

Sanctus

Sanctus, Sanctus, Sanctus,
Dominus Deus Sabaoth!
Pleni sunt coeli et terra gloria tua.
Osanna in excelsis.

Benedictus

Benedictus

Benedictus qui venit in nomine Domini.
Osanna in excelsis.

Agnus Dei

Agnus Dei

Agnus Dei, qui tollis peccata mundi,
dona eis requiem.
Agnus Dei, qui tollis peccata mundi,
dona eis requiem sempiternam.

Communion

Lux aeterna/Cum sanctis tuis

Lux aeterna luceat eis, Domine,
cum sanctis tuis in aeternum,
quia pius es.
Requiem aeternam dona eis, Domine,
et lux perpetua luceat eis,
cum santis tuis in aeternum,
quia pius es.

While I am not personally very familiar with the historical details surrounding Mozart's Requiem, the liner notes that came with my copy (released under the Naxos label) say:

"In July 1791, [Mozart] received a commission for the composition of a Requiem Mass from Count Franz Walsegg zu Stuppach, who sought to commemorate the recent death of his wife by the performance of a work of this kind, which he would claim as his own. To commission the music he sent his steward Franz Anton Leutgeb to Mozart and paid an advance of 60 ducats, with a promise of a further sum when the work was finished."

Though the rest seems quite consistent with Jet-Poop's writeup above.

A few more points of interest:

• It is said that Mozart burst into tears and could go no further when it came to the Lacrimosa, of which he only had written the first eight bars.
• Mozart passed away five minutes to one on the morning of December 5th, to be buried a day or so later in an unmarked grave.
• After her husband's death, Constanze Mozart claimed that he had a premonition that the Requiem was an omen of his own coming death.
• Though it was expected that Constanze would entrust the completion of the work to Mozart's pupil and constant companion Franz Xavier Süssmayer, instead she asked Josef Eybler. He later gave up the task and the unfinished score fell to Süssmayer in the end anyway.