François-Joseph Fétis was a Belgian musicologist, composer, critic and teacher. He was one of the most influential music critics of the 19th century, and his enormous compilation of biographical data in the Biographie universelle des musiciens remains an important source of information today. His wife, Adélaïde Robert, was the daughter of the French politician Pierre-François-Joseph Robert.
Although known primarily for his contributions to musicology and criticism, Fétis had effects on the realm of music theory as well. In 1841 he put together the first history of harmonic theory, his Esquisse de l'histoire de l'harmonie. Assembled from individual articles that Fétis published in the Revue et Gazette musicale de Paris around 1840, the book predates Hugo Riemann's more well knownGeschichte der Musiktheorie by fifty years. The Esquisse, as the title implies, is a general outline rather than an exhaustive study. Fétis is attempting to show the "facts, errors, and truths" of previous theories and theorists, as he interprets them, in order to provide a solid grounding for other scholars and to prevent subsequent interpretive mistakes.