I am surprised that no one has mentioned the great film scores from the 1930s 1940s and 1950s by such composers as
Korngold (Adventures of Robin Hood; The Sea Hawks)
Steiner (Gone With The Wind; Now Voyager)
Waxman (Bride of Frankenstein; A Place In The Sun) and
Rozsa (Ben-Hur; El Cid)
All of these composers were heavily influenced by Gustav Mahler (Death in Venice) and they in turn influenced Bernstein; Morricone; and Williams.