By far the most significant contribution of France to music in the Renaissance period was the chanson. The chanson was a variety of secular song, of highly varied character, and which included some of the most overwhelmingly popular music of the 16th century: indeed many chansons were sung all over Europe. The chanson in the early 16th century was characterised by a dactylic opening (long, short-short) and contrapuntal style which was later adopted by the Italian canzona, the predecessor of the sonata. Typically chansons were for three or four voices, without instrumental accompaniment, but the most popular examples were inevitably made into instrumental versions as well. Famous composers of these "Parisian" chansons included Claudin de Sermisy and Clément Janequin. Janequin's "La guerre", written to celebrate the French victory at Marignano in 1515, imitates the sounds of cannon, the cries of the wounded, and the trumpets signaling advance and retreat. A later development of the chanson was the style of "musique mesurée", as exemplified in the work of Claude Le Jeune: in this type of chanson, based on developments by the group of poets known as the Pléiade under Jean-Antoine de Baïf, the musical rhythm exactly matched the stress accents of the verse, in an attempt to capture some of the rhetorical effect of music in Ancient Greece (a coincident, and apparently unrelated movement in Italy at the same time was known as the Florentine Camerata). Towards the end of the 16th century the chanson was gradually replaced by the air de cour, the most popular song type in France in the early 17th century.