Bluegrass legend Ralph Stanley has died. The Appalachian music patriarch helped to expand and popularize the bluegrass sound. He was 89.

His publicist says Stanley died Thursday. Stanley was born and raised in southwest Virginia. He and brother Carter formed the Stanley Brothers and their Clinch Mountain Boys in 1946. The brothers fused Grand Ole Opry star Bill Monroe's rapid rhythms with the mountain folk of groups such as the Carter Family, and added a distinctive three-part harmony.

Carter Stanley died of liver disease in 1966. Ralph Stanley's "O Death" from the "O Brother, Where Art Thou?" movie soundtrack introduced him to a new generation of fans in 2000. He won a Grammy for best male country vocal performance in 2002.