Canon is a term that derives from the Greek “kanón”, used to designate a rod that served as a reference as a unit of measure. In Portuguese, the term acquired the general meaning of rule, precept or standard. In certain contexts, the word canon can have more specific meanings.
In literature, it is a set of books considered as a reference in a certain period, style or culture. "Macunaíma", by Mário de Andrade, or "Grande Sertão: Veredas", by Guimarães Rosa, can be considered canon works of Brazilian literature.
In the context of religion, a set of books considered to be of divine inspiration. In the Catholic religion it is also the name given to one of the parts into which the liturgy or the rules established in a council are divided.
Canon in the arts
In Fine Arts, canon was a rule that establishes the ideal proportions of the human figure. The Vitruvian Man, by Leonardo da Vinci, is considered a canon of human proportions. Later it was also applied in architecture. Its main theorists were Policleto, Leonardo da Vinci (Tratatto Sulle Proporcioni) and Dürer, among others.
musical canon
In music, canon is a composition of two or more voices singing the same melody, which is characterized by the fact that these voices are sung out of phase in time. O canon of Pachelbel is one of the famous compositions in this style. Chico Buarque composed the song "Sem Fantasia" in the canon style.
It is the strictest form of imitative style. The voices, of unlimited number, successively enter at exact distances, and are equal in their extension, complementing each other, however, harmonically, which is why also in polyphony it is necessary to take into account the concept of harmony, although taken in a sense different.
It is important to add that the distance of the intervals can be different (canon to unison, to octave, to second, etc).
Originally, the canon is one of the oldest forms of the art of counterpoint, as it has its roots in choreographed corners (rondellus, route) used in folk music and dates back to the 13th century, which can be proven by the famous English canon Summer is icumen In.
The cultivation of the canon reached its zenith in the 15th-16th centuries in Holland. J.S. Bach was immortalized in the Goldberg Variations, published in 1741.