William James Matthias (1934–1992) was a Welsh composer known primarily for his contributions to contemporary classical music. His work is characterized by a distinctive blend of traditional forms and innovative harmonic language, often drawing on influences from both folk music and modernist techniques. Matthias studied at the Royal Academy of Music and later at the University of Cambridge. Some of his notable works include his symphonies, concertos, and choral pieces, with "Sinfonia" and "Concerto for Orchestra" standing out among his orchestral compositions. He also composed a considerable number of chamber works and vocal music, showcasing his versatility across genres. Matthias's impact on music is marked by his ability to bridge the gap between traditional classical music and contemporary styles, earning him recognition within the British music scene. He served as a professor of composition at the University of Wales and was influential in educating the next generation of composers. His music remains a part of the repertoire of various ensembles, reflecting a significant contribution to 20th-century classical music.