Classical Composers are not by and large particularly morbid people, but death and music go so well together, that the combination can be hard to resist. The centuries of this music have supplied a stock of aural gestures to signify life ending: dark, bruised chords, demonic rhythms, violin bows trembling near the bridge, making gnashing screeching sounds etc.
It's not only the doom-laden meditations such as Shostakovich's 15th String Quartet or the sublime expressions of grief such as R. Strauss' Metamorphosen or Mahler's Kindertotenlieder. Or the reference to death as the vital force in romantic Opera, propelling the drama towards its triumphant melodious bloodbath.
It's also the music dealing with the thing itself: that imagines what it is like to die. The wellspring of most death-related music is the Dies Irae chant, a not particularly doom-laden medieval melody to the prayer for departed souls. The chant got its anthemic status during the 19th century, when a great deal of romantic composers slowed it down, cranked it up and had the brass pound it into a terrifying zombie-like march. In Berlioz's Symphonie Fantastique, the tune is used as the dramatic centerpiece, where Death is a grotesque, a dancing comic character who taunts the living with raucous music.
Liszt, a virtuoso pianist of rock star standing and a composer of mystical bent had his own exquisite fascination with mortality, contributing copiously to the morbid-symphonic repertoire. His masterwork in the genre is Totentanz, a ferociously lugubrious showpiece for piano and orchestra, where he uses the "Dies Irae" in all its pounding majesty, embroidering it with so much hyperactive passagework for the piano, that playing the piece itself can be nearly lethal! Liszt treats mortality by fashioning an ode to death as a heroic stage in life, a titanic struggle for immortality.
The list can go on, showing that composers update the question of Death in Classical Music from the very start (Victoria, Tallis, Schutz), through the centuries (Mozart, Schubert, Berg) up to our times (Shostakovich, Britten, Crumb).
So, what's your views on the matter. Is such an issue a driving force in Classical Music? Is it an inspiration that lies practically everywhere, in almost every composer and most of the works, in one or the other way? Is it, perhaps, the other side of the same coin (life affirmation). Can you provide your examples of great (or bad) music inspired by the subject of mortality or death fear?
Let's illuminate the dark and the unknown.