Correction: Mozart’s Requiem isn’t a symphony, it’s a requiem: a type of Catholic mass for the dead. It was initially written for mass but later popularized and performed outside the church, as was Verdi's.
Think back to some of the most dramatic scenes in film history — from The Lion King, The Shining, It’s a Wonderful Life. Besides being sad or scary, they have something else in common: the dies irae. “Dies irae” translates from Latin to “Day of Wrath” — it’s a 13th-century Gregorian chant describing the day Catholics believe God will judge the living and the dead and send them to heaven or hell. And it was sung during one specific mass: funerals.
As Catholicism permeated world culture, the melody of the chant was repurposed into classical music, where it was used to convey a deathly, eerie tone. From there it worked its way into films — and if you don’t already know it, you’ve almost certainly heard it before: It’s played over and over in our scariest and most dramatic cinematic moments.
Here’s Alex Ludwig’s original supercut of movies featuring the dies irae: https://youtu.be/GLGa6vfDTIM