Francois Joseph Fetis was a Flemish musical theorist and composer. He was born in 1784 and died in 1871. He was educated at the Paris Conservatoire; was professor there from 1818 to 1833, when he was appointed director of the Conservatoire at Brussels. Among his works may be mentioned Traite de la Fugue (1825); Biographie Universelle des Musiciens (1835-1844); Traite Complet de la Theorie et de la Pratique de l'Harmonie. His musical compositions include operas, sacred music, and instrumental pieces for the piano and the violin and he founded the Revue Musicale. Research Francois Fetis
A canon is a musical composition in which the voices begin one after another, at regular intervals, successively taking up the same subject. It either winds up with a coda (tailpiece), or, as each voice finishes, commences anew, thus forming a perpetual fugue or round. It is the strictest form of imitation. Research Canon
A fugue is a polyphonic musical composition, developed from a given theme or themes, according to strict contrapuntal rules. The theme is first given out by one voice or part, and then, while that pursues its way, it is repeated by another at the interval of a fifth or fourth, and so on, until all the parts have answered one by one, continuing their several melodies and interweaving them in one complex progressive whole, in which the theme is often lost and reappears. Research Fugue