The Canon and Gigue in D major by Johan Pachelbel, popularly known as Pachelbel's Canon is one of the most popular baroque pieces to be performed to the day. Like other works by pre 1700 composers, it remained undiscovered for centuries, only to be published in 1919 by Gustav Beckmann, as part of his article on Pachelbel's music. The date and circumstances surrounding the composition remain unknown, though much has been guessed (one popular theory poses that it was written for Johann Christoph Bach's, brother of Johann Sebastian, for the occasion of his wedding, as Pachelbel is supposed to have taught him at some point).
The piece, originally scored for a trio of violins and continuo, is nowadays performed by many different instrumental ensembles (almost always omitting the gigue). It is technically a canon at the unison in three parts, though it has a fourth independent part which plays a ground bass.
Since its publication the piece has become extremely popular, and its chordal progression has become something of a stock resource for songwriting. Thus, many popular songs and pieces are said to be influenced by it.