What genre did the motet replace as the major polyphonic genre in the 13th century?

The motet emerged as a significant polyphonic form in the 13th century, effectively replacing organum as the predominant polyphonic genre of the time. Organum, which originally involved the addition of one or more voices to a plainchant melody, was one of the earliest forms of polyphony. As musical styles evolved, composers began to develop the motet, which featured more complex structures and greater freedom in text and music. The motet allowed for the combination of different texts (often in different languages) sung simultaneously, showcasing more intricate counterpoint and musical innovation. This evolution was part of a broader shift in medieval music that moved toward more secular influences and personal expression, which the motet encapsulated beautifully.

In contrast, genres like the Mass and secular song existed concurrently with the development of the motet but did not replace organum in the same manner. The Mass is a liturgical work, and while it did incorporate polyphonic elements, it did not specifically take the place of organum as the prevailing polyphonic form. Similarly, secular songs, while prevalent in the 13th century, did not reach the same level of complexity or prominence in polyphonic music as the motet did during this transformative period.