Firminus Caron was a French composer, and likely a singer, of the Renaissance. He was highly successful as a composer and influential, especially on the development of imitative counterpoint, and numerous compositions of his survive. Most of what is known about his life and career is inferred. Caron left both sacred and secular music, including five masses and numerous secular songs. One of the earliest masses based on the famous tune L'homme armé is by Caron, and survives in an early 1460s Vatican manuscript along with L'homme armé masses by several other composers. In Caron's setting the tune is transposed to Dorian mode and elaborated considerably; the upper voices often sing in two-part imitation. Most of his secular songs were in French, and for three voices, and most survive from Italian manuscripts. Most are rondeaux, and most are in duple meter. One of his songs,Helas que pourra devenir, was extraordinarly famous, and was the second-most-widely distributed song in manuscript sources of the third quarter of the 15th century (De tous biens plaine, by Hayne van Ghizeghem, was the first). It is unusual among songs of the time in using very close imitation, and it seems to have initiated a trend. David Fallows, writing in the New Grove, hypothesises that it may have originated as an instrumental fantasy.