His main contribution was the publication in 1587 of the theoretical treatise on the practice of painting, titled De veri precetti della pittura.
In the first book, he speaks of major Renaissance and Mannerist painters of the past including Raphael, Michelangelo, Titian, Antonio da Correggio, Sebastiano Veneziano, Giulio Romano, and Andrea del Sarto.
[6] Contemporary theoretical books had been published based on writings of Leonardo da Vinci, Giovanni Paolo Lomazzo, and Leon Battista Alberti.
Remembering as example of a complete artist "the painter, who was almost a miracle, that accompanied with Architecture, and with histories, the Painting, the Music, and the Poetry was first Gitto Fiorentino",[9] Armenini shows an extraordinary modernity in the composition of the catalog "fine arts".
[12] All these ideas will migrate along decades, and we find them almost identical in later theorists, as in the famed Batteux in his treatise "Les beaux arts réduits à un même principe"