The plainchant "Dies irae" has been used in the Extraordinary Form of the Roman Rite liturgy as the Sequentia/Sequence for the Missa pro defunctis or Mass for the Dead for centuries and is published in the Liber Usualis (edition 1936 pages 1810-1813). The text of this "Dies irae/the Day of Wrath" is in the literature attributed either to Thomas of Celano of the Franciscans (1200–1265) or to Latino Malabranca Orsini (d. 1294). Due to reforms since 1969-70 this famous hymn and in total the Sequence is eliminated from funerals and Masses for the Dead. Fortunately very imposing settings have been left in all following centuries by distinguished composers since the Renaissance. The first remaining polyphonic Requiem-settings to include the "Dies irae" are by Engarandus Juvenis (c. 1480-1520) and by Antoine Brumel (c.1460-c.1513) to be followed by many composers of the renaissance and later. We think the “Dies Irae” by Brumel is the first still remaining polyphonic setting. Brumel sets his “Dies Irae” around 1510.
Around 1615 Gregor Aichinger sets an Officium pro defunctis 5vv published Augsburg in 1615. But this setting is lost. This Officium was probably occasioned by the death and funeral of emperor Rudolf II ( 1552-1612). Earlier in 1597 Aichinger sets a “Dies Irae, dies Illa” for five voices (SQATB). These setting contains not the complete “Dies Irae”, only the first eight strophes are published. This found setting is attributed to Aichinger. Aichinger sets this composition in a predominantly homophonic way, with some polyphonic imitation. The whole piece is set in D-Dorian. The fourth strophe “Mors” and the sixth strophe ”Judex” are set in A-Aeolian. In the first Strophe the plainchant is quoted by the Altus (in Ms 1-3).
Aichinger uses in this motet syncope’s, flats and sharps and some important part of sentences will be repeated. In “Mors/Death” Aichinger uses a refined approach with descending semitones in Tenor, Altus f-e and in the Bassus d-c#. In this fourth strophe (Ms 52-56) ) Aichinger uses changing minor keys and every part starts with intervals after each other beginning by Tenor ending by Bassus, This chosen method amplifies strongly the word “Mors/Death.” In the fifth strophe Aichinger starts only with the three upper parts in an imitative way (Ms 70-80) culminating with all the parts in a proportio tripla 3/2 “Unde mundus iudicetur” (Ms80-84).Those important words meaning ‘ the whole world shall be judged’ will be repeated (Ms 85-89). This “Dies Irae” ends with the eight strophe starting with a homophonic “Rex tremendae majestatis” and ends with a polyphonic but begging “Salva me/safe me” which will be sung twice.
This motet consists out of 148 bars and is published in Sacrum cantionum a 5-8 vocum (Gregor Aichinger), Noribergae: apud Paulum Kauffmannum MDXCVII.

Text:
I Dies iræ, dies illa,
Solvet sæclum in favilla:
Teste David cum Sibylla.

II Quantus tremor est futurus,
Quando Iudex est venturus,
Cuncta stricte discussurus!

III Tuba, mirum spargens sonum
Per sepulchra regionum,
Coget omnes ante thronum.

IV Mors stupebit, et natura,
Cum resurget creatura,
Iudicanti responsura.

V Liber scriptus proferetur,
In quo totum continetur,
Unde mundus iudicetur.

VI Iudex ergo cum sedebit,
Quidquid latet, apparebit:
Nil inultum remanebit.

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

VIII Rex tremendæ maiestatis,
Qui salvandos salvas gratis,
Salva me, fons pietatis.

Amen

Translation
I Day of wrath! O day of mourning!
See fulfilled the prophets' warning,
Heaven and earth in ashes burning!

II What trembling there will be
When the judge shall come
to weigh everything strictly!

III The trumpet, scattering its awful sound
Across the graves of all lands
Summons all before the throne.

IV Death and nature shall be stunned
When mankind arises
To render account before the judge.

V The written book shall be brought
In which all is contained
Whereby the world shall be judged

VI When the judge takes his seat
all that is hidden shall appear
Nothing will remain unavenged.

VII What shall I, a wretch, say then?
To which protector shall I appeal
When even the just man is barely safe?

VIII King of awful majesty
You freely save those worthy of salvation
Save me, found of pity.
Amen

The plainchant Peccantem me Quotidie is an old Responsorium/Respond from Matins of the Dead and is published in the Liber Usualis (ed. 1936 page 1797) after Lectio VII/Lesson VII. The plainchant Peccantem me quotidie is an old Respond. There are about 138 Responsoria known used during centuries in the Office of the Dead. It’s interesting here Aichinger uses as second part the Versicle of the Respond Domine quando veneris from the Matins of the Dead which is sung after Lectio/Lessons III.
More important the used Versicle Commissa mea Domine pavesco – see among others a setting by Filipe Magalhães ( c.1571-1652) and other Iberian composers her on site - is even known as Versicle no.34 from Matins of the Dead and described in the Responsories and Versicles of the Matins of the Dead. In a lot of sources this Versicle is even attached to four! different Responsories among others to the here discussed Respond Peccantem me quotidie especially found in Münster Germany 14th century in this case. See for instance the “Peccantem me Quotidie” set by Jacob Regnart (c.1540-1599) which uses the same Versicle “Commissa mea”. So in the German Region a well known combination. The choice of texts and the order in which they occur in the sources vary according to local uses! This motet Peccantem me Quotidie is written by Aichinger for four voces CATB in a fluent counterpoint style. Cantus starts followed by Altus, Tenor and Bassus. Aichinger uses the general used Respond text up to bar 53. From bar 54 Aichinger starts with the Versicle “Commissa mea ”. It’s interesting to follow Aichinger in its setting of this Versicle particularly where Aichinger repeats the same musical figure a sort of humble pleading in all voces (from bar 72 up to the end) with the same notes f-d-e-f in “Noli me condemnare”, “do not condemn me!” After that Achinger uses the same text and musical figures with some variations due to the chosen mode. This splendid setting ends in full a-Phrygian.
This motet consists out of 93 bars and is published in Sacræ Symphoniae quaternis, V. VI, VII, VIII, X, XII tam vocibus, quam intsrumentis. Editio NOVA, Nuribergae, apud Paulum Kaufmann, (1598).

Officium pro defonctis quinque vocibus, (for 5 voices) was published in Augsburg, 1615.

Early in the 17th century the Renaissance polyphonic style, in various modified forms, served for several decades as a principal medium for requiem composition. A fine example, in Palestrinian style, is G.F. Anerio's setting (published in 1614, and reprinted three times up to 1677), the 'introit' of which reveals an elegant use of chant paraphrase. Similar in approach, but with more archaic cantus firmus treatment, are the expressive settings of two of Victoria's successors, Duarte Lobo (Officium defunctorum, 1603) and J.P. Pujol (Requiem for four voices, before 1626). An important innovation, evident in a number of works, is the inclusion of an organ continuo part (with figured or unfigured bass), which allowed greater variations in texture and dynamics. Early examples include Aichinger's Requiem (1615; D-As) and settings, from 1619, by Antonio Brunelli and Jean de Bournonville.