One of my favorite pieces of music is "Ashokan
Farewell". Jay Ungar composed it in
1982. I listened to and loved it before it became a famous part of Ken Burn's Civil War series.
For the back story on this beautiful music:
https://www.theatlantic.com/entertainment/archive/2015/09/ashokan-farewell-how-a-20th-century-melody-became-an-anthem-for-the-19th/407263/