Circolo mezzo
Semicircular ornamental figure.
What it means
Circolo mezzo — “half circle” — designates an ornamental figure that circles the main note: the melody leads via an auxiliary note back to the starting note and thereby describes an arc-shaped movement. The Italian name belongs to the figure designations of the Baroque doctrine of ornamentation, in which numerous such figures bear names of their own.
The earliest precise description comes from Wolfgang Caspar Printz, in the second part of his Phrynis Mitilenaeus oder Satyrischer Componist (1696): in the circolo mezzo, four quick notes form a semicircle on the page, with either the first and third or the second and fourth notes on the same pitch. When the figure rises, Printz calls it intendens; when it falls, remittens. Johann Gottfried Walther includes the term in his Musicalisches Lexicon (1732), where two circoli mezzi joined together make up the circolo, a figure of eight quick notes.
In effect the figure stands close to the turn, which likewise plays around the main note with its neighbouring notes. The boundary between the transmitted figures is blurred, because the textbooks of that time know different designations and executions and the terminology differs from author to author.
Whoever works with such terms should therefore always bear in mind the source from which a designation comes.
In the notation
There is no separate, generally used sign. In the historical ornament tables the figure is presented written out, that is, notated in its execution. In modern editions of early music such figures appear either written out or explained in a footnote.
Musical use
Ornamental figures of this kind belong to the practice of diminution: longer note values of a given melody are broken down into smaller ones and embellished in the process. Singers and instrumentalists of the sixteenth and seventeenth centuries learned such figures as a stock from which they drew in performance. They typically stand at cadences and on long notes.
Performance practice
Execute the figure lightly and without emphasis; it adorns the main note, it does not replace it. Take care that the goal note stays on its beat. Keep the notes of the figure even instead of lengthening the first. And, when performing, consult a historical ornament table if the edition names a source — ideas on this differ.