The Monroe Brothers were a popular American bluegrass duo formed in the 1930s, consisting of Charlie Monroe and Bill Monroe. They are known for their harmonious vocals and innovative guitar and mandolin playing, which helped shape the bluegrass genre. Their music often featured traditional Appalachian themes and showcased their unique blend of folk and country influences. The brothers gained recognition for their performances and recordings, contributing to the rise of bluegrass music in the United States. Bill Monroe later became known as the "Father of Bluegrass," establishing his own band, the Blue Grass Boys, which further popularized the style. Their legacy continues to influence musicians today.