Rondo and the part-equivalent French term, rondeau, are words long used in music in a number of ways, most often in reference to a musical form. Despite the common etymological root, rondo and rondeau as musical forms are essentially different. Rondo is strictly an instrumental musical form that was developed beginning in the 17th century. Rondeau, on the other hand, is a vocal musical form that was originally developed as monophonic music and then as polyphonic music. Notably, both vocal forms of rondeau nearly disappeared from the repertoire by the beginning of the 16th century.
Form
In rondo form, a principal theme alternates with one or more contrasting themes, generally called "episodes", but also occasionally referred to as "digressions" or "couplets". Possible patterns in the Classical period include: ABA, ABACA, or ABACABA. These are sometimes designated "first rondo", "second rondo", and "third rondo", respectively. The first rondo is distinguished from the three-part song form principally by the fact that at least one of the themes is a song form in itself, but the difference in melodic and rhythmic content of the themes in the rondo form is usually greater than in the song form, and the accompanimental figuration in the parts of the rondo is usually contrasted. The number of themes can vary from piece to piece, and the recurring element is sometimes embellished and/or shortened in order to provide for variation. Perhaps the best-known example of rondo form is Beethoven's "Für Elise", an ABACA rondo. The pattern of repeats, however, in eighteenth-century ballet music, that is, in music intended specifically for dancing rather than listening, is often not predictable. An instructive example comes from the pasticcio pantomime ballet Le peintre amoureux de son modèle, extant in the Ferrère manuscript. The final contredanse générale, for example, which was taken from J.-P. Rameau’s Les fêtes d’Hébé and which was to be played “en rondeau,” has a repeat structure of AA x 4. A Baroque predecessor to the rondo was the ritornello. Ritornello form was used in the fast movements of baroque concertos, and in many baroque vocal and choral works. The ripieno plays the main ritornello theme, while soloists play the intervening episodes. As typical of Baroque continuo playing, in the tutti sections the soloists also play as part of the ensemble; while in the solo sections most of the remaining instruments in the ensemble may stop, in order to provide some transparency to the soloist, or may be used sparsely. While Rondo form is similar to ritornello form, it is different in that ritornello brings back the subject or main theme in fragments and in different keys, but the rondo brings back its theme complete and in the same key. Cedric Thorpe Davie is one author, however, who considers the ritornello form the ancestor, not of the rondo form, but of the classical concerto form A common expansion of rondo form is to combine it with sonata form, to create the sonata rondo form. Here, the second theme acts in a similar way to the second theme group in sonata form by appearing first in a key other than the tonic and later being repeated in the tonic key. Unlike sonata form, thematic development does not need to occur except possibly in the coda. The last movement of Beethoven's Sonata Pathétique is an example of a sonata rondo.
Rondo as a character-type refers to music that is fast and vivacious – normally Allegro. Many classical rondos feature music of a popular or folk character. Music that has been designated as "rondo" normally subscribes to both the form and character. On the other hand, there are many examples of slower, reflective works that are rondo in form but not in character; they include Mozart's Rondo in A minor, K. 511.
Etymology
The term and perhaps the formal principle may have derived from the medieval poetic form rondeau, which contains repetitions of a couplet separated by longer sections of poetry. However, it has been musicologically preferred that the term rondeau be reserved to the vocal musical form, while the term rondo be reserved for the instrumental musical form.
Other usages
A well-known operatic vocal genre of the late 18th century, referred to at that time by the same name but distinguished today in English and German writing by the differently accented term "rondò" is cast in two parts, slow-fast.
