Fidélium, Deus, ómnium Cónditor et Redémptor: animábus famulórum famularúmque tuárum remissiónem cunctórum tríbue peccatórum; ut indulgéntiam, quam semper optavérunt, piis supplicatiónibus consequántur.
O God, Creator and Redeemer of all the faithful, grant to the souls of Your servants and handmaids the remission of all their sins, that they may obtain by our loving prayers the forgiveness which they have always desired.
The commemoration of all the faithful departed is celebrated by the Church on 2 November, or, if this be a Sunday or a feast of the first class, on 3 November. …
The theological basis for the feast is the doctrine that the souls which, on departing from the body, are not perfectly cleansed from venial sins, or have not fully atoned for past transgressions, are debarred from the Beatific Vision, and that the faithful on earth can help them by prayers, almsdeeds and especially by the sacrifice of the Mass.
In the early days of Christianity the names of the departed brethren were entered in the diptychs. Later, in the sixth century, it was customary in Benedictine monasteries to hold a commemoration of the deceased members at Whitsuntide. In Spain there was such a day on Saturday before Sexagesima or before Pentecost, at the time of St. Isidore (d. 636). In Germany there existed (according to the testimony of Widukind, Abbot of Corvey, c. 980) a time-honoured ceremony of praying to the dead on 1 October.
This was accepted and sanctified by the Church. St. Odilo of Cluny (d. 1048) ordered the commemoration of all the faithful departed to be held annually in the monasteries of his congregation. Thence it spread among the other congregations of the Benedictines and among the Carthusians. …
A similar concession for the entire world was asked of Pope Leo XIII. He would not grant the favour but ordered a special Requiem on Sunday, 30 September, 1888. In the Greek Rite this commemoration is held on the eve of Sexagesima Sunday, or on the eve of Pentecost. The Armenians celebrate the passover of the dead on the day after Easter.
https://www.ecatholic2000.com/cathopedia/vol1/volone463.shtml
In the Extraordinary Form of the Mass, the Dies Irae is recited or chanted.
Not to sperg out here, but the Dies Irae is super popular in contemporary culture, and always has been. Check it out in the following movies. You have to listen diligently in some of these – but it’s there.
Pirates of the Carribean
It’s a Wonderful Life
Lord of the Rings
The Lion King
Star Wars (I’m actually not hearing it here.)
Many In Film Music in General
Last (here at least), and most spectacularly, the Excommunication Scene from Becket.
O God, Lord of mercies, grant to the souls of Your servants and handmaids a lasting place of refreshment, the blessedness of rest and the splendor of Your light.
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