While Wert wrote both sacred and secular music, as well as a handful of instrumental fantasias, his madrigals were by far the most famous portion of his output during his lifetime. He wrote approximately 230, which he published in sixteen separate books spread across a half-century, from 1558 to the final posthumous collection in 1608. His madrigal books are almost all for five voices, although he published one book in 1561 for four, and the posthumous collection of 1608 includes pieces ranging from four to seven voices.