His compositions include large scale works, including an opera, The Servants (1980), three symphonies and three piano concertos. Much of his music was written for the Anglican choral tradition, most famously the anthemLet the people praise Thee, O God written for the July 1981 royal wedding of the Prince and Princess of Wales, which had a television audience of an estimated 1 billion people worldwide.
Mathias wrote his Sinfonietta – initially called Dance Suite – for the Leicestershire Schools Symphony Orchestra (LSSO) in late 1966, and it received its first performance at LeicesterDe Montfort Hall during the 1967 Schools Festival. It was also included in the orchestra's tour programme for Denmark and Germany later in the year. The LSSO made the first commercial recording of Sinfonietta for the Pye Golden Guinea label in July 1967 under the direction of the composer (see external links below).
Toccata Giocosa, Op. 36, No. 2 (1967) dedicated to Sir David Willcocks on the occasion of his inauguration of the new organ at the Royal College of Organists, 7 October 1967
Jubilate, Op. 67, No. 2 (1974) dedicated to Michael Smythe
Fantasy, Op. 78 (1978)
Canzonetta, Op. 78, No. 2 (1978)
Antiphonies, Op. 88, No. 2 (1982)
Berceuse, Op. 95, No. 3 (1985)
Recessional, Op. 96, No. 4 (1986) dedicated to Christopher Morris, musician, publisher, friend
Fanfare (1987)
Carillon (1989)
Fenestra (1989)
Choral
Alleluia! Christ is Risen! (1986)
All Thy Works Shall Praise Thee for choir and organ, Op. 17b
Saint Teilo, cantata for narrator, contralto and tenor solo, boys' and girls' choirs, mixed chorus, organ and chamber orchestra, Op. 21 (Commissioned by and premiered at the 1963 Llandaff Cathedral Festival)
Make a joyful noise, Op. 26, No. 2
Festival Te Deum for choir and organ, Op. 28 (1964)
O Sing Unto the Lord for choir and organ, Op. 29
Three Medieval Lyrics for choir and instrumental ensemble, Op. 33
An Admonition to Rulers, Op. 43
Psalm 150 for choir and orchestra, Op. 44
Lift Up Your Heads, O Ye Gates, Op. 44, No. 2 (1969)