Contrapuntal Device

Imitation, Canon & Round

When the parts in a piece of polyphonic music share melodic ideas, they are said to be in imitation. If the imitation is exact and continues through the whole piece, the piece is called a canon. A portion of a piece is described as canonic if the imitation persists throughout the section. In describing points of imitation there are two crucial measurements to consider: (a) the distance between leader and follower in time; and (b) the interval distance between the first note of the leader and that of the follower. Sixteenth-century canons often use interval distances of a perfect fourth or fifth as well as octave and unison.

A round is a familiar type of canon where the time distance is the length of a complete phrase and the interval distance is a unison (or an octave when men and women sing together). Rounds are cyclic: as each voice reaches the end, it begins again. A round is normally sung as many times through as there are voice parts.

Examples:

• Imitation: Palestrina Kyrie from Missa Papae Marcelli — Late Renaissance masses and motets often feature points of imitation.
• Canons:
  • Bach Canon alla Ottava from The Art of Fugue — Scroll to PDF page 11.
  • Bach Invention No. 2 in C minor BWV 773
  • Bach Goldberg Variations BWV 988 (1741) — Every third variation
  • Bach crab canon from the Musical Offering (1747)
  • Haydn String Quartet, op. 76, no. 2 — Scroll to the minuet on p. 128.
  • Mozart Menuetto and Trio from the Wind Serenade in C minor K. 388
• Rounds:
  • Are You Sleeping?
  • The Bell Doth Toll
  • The Crane
  • Da pacem, Domine (Note the transpositions.)
  • Dona Nobis Pacem (Music-for-Music-Teachers.com)
  • Dona nobis pacem
  • Early to Bed (Wide range!)
  • Good Night To You All
  • Merrily, Merrily
  • Segne, Vater, diese Gaben
  • Sweetly Sings the Donkey
  • O wie wohl ist mir am Abend (What we hear.)

Source: https://www3.northern.edu/wieland/theory/parts/imitate.htm