Maurice de Jong (born 5 September 1973), known by his moniker Mories, is a Dutch composer and musician. He is best recognized for his multiple music projects, namely Gnaw Their Tongues, Seirom, Aderlating, Cloak of Altering and De Magia Veterum. His compositions are informed by ambient music, black metal, drone music, electronic music and the avant-garde. His interests lie in invoking a disquieting and nightmarish atmosphere with his music, which often utilizes distortion and dissonance. Lauded as a most prolific composer, de Jong has recorded an upwards of three albums per year since 2007.
Maurice de Jong began performing with bands in 1988, most of whom were influenced by black metal, death metal and doom metal. In the early nineties he performed with Cauteror and Soulwound, who performed lengthy songs that emphasized a depressing atmosphere, traits that de Jong would later adopt in his solo work. He started his own solo project in 1993, named Astral. Inspired by the Greek black metal outfit Necromantia, the music omitted the use of the electric guitar, with the electric bass guitar playing an integral role in the compositions. Several demo tapes were recorded between 1993 and 1994.