Though born in the Netherlands, composer Marinus de Jong (1891 - 1984) traded his Dutch citizenship for a Belgian one in 1926, and is considered one of Belgium's most prominent composers and pianists of the 20th century. He began his studies at the Royal Conservatory of Music in Antwerp, Belgium, at the age of 15, studying under Lodewijk Mortelmans and Emile Bosquet. His Sonata for Viola Solo, Op. 106 (Sonate voor altviool solo), published by Metropolis Music Publishers in 1973, is a masterful work in four movements. It demonstrates not only his compositional style, sometimes playful and jazzy, other times plaintive and improvisatory, but also his familiarity with the viola, an instrument which he also played.