Gram Parsons

Gram Parsons (November 5, 1946 – September 19, 1973) was an American singer, songwriter, guitarist and pianist. Parsons is best known for his work within the country genre; he also mixed blues, folk, and rock to create what he called "Cosmic American Music". Besides recording as a solo artist, he also worked in several notable bands, including the International Submarine Band, The Byrds, and The Flying Burrito Brothers. His career, though short, is described by Allmusic as "enormously influential" for both country and rock, "blending the two genres to the point that they became indistinguishable from each other."

source: Wikipedia