Armand-Louis Couperin was a French composer, organist, and harpsichordist of the late Baroque and early Classical periods. He was a member of the Couperin family of musicians, of which the most notable were his great uncle Louis and his cousin François. References to Couperin by his contemporaries, including Charles Burney, laud his improvisational virtuosity (often on the Te Deum hymn) and established his reputation as one of the two best organists of the era. Nevertheless, only one piece for organ exists today. Couperin did not publish his church music and he refused to write for the theater. His surviving works are almost exclusively for the keyboard. Unlike many of his contemporaries, Couperin remained attached stylistically to la grande tradition française, and his pieces have been criticized for their lack of modernity. However, David Fuller cites his experimental impulse and urge to explore the possibilities of instruments. An example is his Simphonie de clavecins, the only work in existence that requires two harpsichords with genouillères (knee-levers that allowed diminuendos).