Rebecca Clarke (1886–1979) was an English composer and violist, best known for her chamber music featuring the viola. She is considered one of the most important British composers in the period between World War I and World War II; she has also been described as the most distinguished British female composer of her generation. Clarke was born on the 27th August 1886 in Harrow on the Hill, Middlesex, England, to Joseph Thacher Clarke, an American, and his German wife, Agnes Paulina Marie Amalie Helferich.