There are clear differences between Rondo and Ritornello form:
In a piece of music in rondo form, the main theme (A) keeps ‘coming round’, with contrasting sections of music called episodes heard in between.
• Rondos can have many episodes and so the main theme then comes round more often. A link may join sections smoothly together and a the ﬁnal appearance of the main theme may be followed by a coda.
• Each time the main rondo theme returns it may be shortened or somehow varied, but it is ALWAYS IN THE TONIC KEY, while each of the episodes visits a related key.
The Italian word ‘Ritornello’ means a ‘little return’. The main ritornello theme is introduced by the whole orchestra, the tutti (all) group, also called the ripieno (full) if more than one player per part.
• The recurring ritornello theme alternates with solo passages of episodes played a smaller group of soloists (the concertino).
• It is very similar to Rondo Form in that the main theme may return whole or in parts, but, unlike Rondo form, it can RETURN IN DIFFERENT KEYS. Even so, the ﬁrst and last occurrence of the main theme is usually the whole ritornello theme played in the tonic key.
• Also, unlike Rondo Form, the episodes are played by a soloist or group of soloists. They may introduce new musical ideas or base their music on ideas taken from the Ritornello.
• Ritornello form was often used in the fast (and sometimes the slow) movements of Baroque concertos - solo and concerti grossi - but it was also sometimes used in arias and choruses from operas, cantatas and oratorios.