This third volume of the selected musical pieces from the Hren choirbooks presents three settings of the Ordinary by Simone Gatto (c. 1545/50–1594/95), a Venetian musician active at the Inner-Austrian archducal court in Graz: a Missa Aller mi fault, a Missa Stabunt justi and a Missa Andra la nave mia. All three Masses are of the parody or imitation type, each derived from a pre-existing polyphonic composition. Specifically, Adrian Willaert’s five-part chanson Aller m’y faut sur la verdure and Orlando di Lasso’s five-part motet Stabunt justi serve as the models for two of the Masses, while the source for the third Mass remains unidentified. These compositions reflect the changing aesthetic preferences of the period, characterized by a heightened emphasis on colour contrast and word-painting. The Missa Andra la nave mia further exemplifies the increasing esteem for polychoral music at the Graz court towards the close of the sixteenth century, illustrating the growing influence of double-choir music in Inner Austria during this time. Gatto’s craftsmanship clearly marks out these three Masses as the product of an experienced composer.