Baroque Solo Concerto

The Baroque solo concerto pairs a single instrumental soloist (typically violin, but also oboe, flute, cello or harpsichord) with a small string orchestra and basso continuo (cello plus harpsichord or organ realizing figured bass). The standard form is three movements — fast, slow, fast — built around the ritornello principle: an orchestral refrain in the home key opens the movement and returns at structural points, while the soloist plays episodes between the ritornellos that modulate and develop the material. The Italian models codified by Vivaldi in the early 18th century became the European template.

The form crystallized in Italy between roughly 1690 and 1720. Giuseppe Torelli of Bologna wrote some of the earliest examples for violin. Antonio Vivaldi (1678-1741), violin teacher at the Ospedale della Pieta in Venice (a girls' orphanage with an extraordinary in-house orchestra), wrote over 500 concertos and set the three-movement ritornello template. His 'L'estro armonico' Op. 3 (1711) was widely circulated in print and studied across Europe, including by J.S. Bach, who transcribed several Vivaldi concertos for keyboard. The 'Four Seasons' (1725) added programmatic sonnets to the form.

Listen for the ritornello returning in different keys throughout the movement — the same melodic idea will reappear in the minor, in a related key, and finally back home. The soloist's episodes between ritornellos are where modulation and virtuosity happen. The basso continuo keeps a relentless walking pulse that supports the soloist's freedom.

Start with 'Spring' from Vivaldi's 'Four Seasons' Op. 8 No. 1 (1725) — the form is unusually clear because the published sonnet describes each section. For Bach's deeper writing try the Violin Concerto in A minor BWV 1041 (c. 1730); for keyboard concerto try the Harpsichord Concerto in D minor BWV 1052.

Vivaldi's Pieta orphanage in Venice was famous across Europe for the quality of its female musicians; foreign visitors traveled specifically to hear them perform. The girls played from behind metal grilles that obscured them visually, an arrangement that fascinated Rousseau when he visited in the 1740s.