Bill Monroe, 13 years older than Scruggs, was prominent in country music at the time. His career started with the "Monroe Brothers", a duo with his brother Charlie. Bill sang the high tenor harmony parts, a sound called "high lonesome", for which he became noted. The brothers split up in 1938 and Bill, a native of "the Bluegrass State" of Kentucky, formed a new group called Bill Monroe and the Blue Grass Boys. They first played on the Opry in 1939 and soon became a popular touring band featuring a vocalist named Lester Flatt. The name "bluegrass" stuck and eventually became the eponym for this entire genre of country music and Monroe became known as "the father of bluegrass."