This chapter examines the effect of humanism on the Latin poetry set by fifteenth-century composers, primarily from the formal point of view. By the early sixteenth century, humanism had made quantitative meters almost the only acceptable vehicle for Latin poetry and encouraged the composition of music that at least to some extent respected the meter of the texts. Guillaume Du Fay's Latin motets have texts of varied styles and merit; the only one that speaks in his name is in elegiac couplets, and the quantitative poems likeliest to be his own work are by no means the worst. The setting of classical poetry revived a practice known from the tenth to the twelfth centuries, which would be much favored in the sixteenth, especially with passages from the fourth book of the Aeneid relating to Dido and Aeneas.