Byrd, burd, William (1543-1623), was an English composer known for his religious music. Byrd wrote three masses and many choral works called motets for the Roman Catholic Church. He also wrote anthems and psalms for the Church of England. In addition, Byrd composed nonreligious works for chorus and solo voice and chamber music for viol, a stringed instrument that was popular during the 1500's. Seventy of Byrd's compositions for the virginal, an early small harpsichord, are included in a famous collection called the Fitzwilliam Virginal Book (about 1625).