This question could literally have over one million different comments, and they would probably all be right. Example, "Only Time" by Enya, a song I never heard until 9/11/01. When JFK was assassinated in November of 1963 he was honored with Scottish Bagpipers. When my dad passed away in January of 2004, I listen to "He Stooped Loving Her Today" by George Jones, because it was my dad's favorite song. As for me personally, well it is Foolish Games by Jewel, because of things that have personally effected me in my life. And now to try and answer your question as a whole, I think it would be Mozart. All that he went through, and even endured in his life, and to see how much his music is loved today as well throughout history. Of course this is only my opinion.
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That's a tough one @JAYDADDY. So many great artist have made their mark on history and pushed the boundaries of what great music is. ( I plan on editing this more later but a few for me personally)
Lil Nas X