Lomazzo, a friend and frequenter of Melzi, a pupil and heir of Leonardo's manuscripts, was able to know the writings of the master and to remember them repeatedly in his works, and therefore also in the Treatise on the art of painting, printed in Milan for the first time in 1584. Lomazzo was also the owner of writings on the arts of the master, and thanks to these he provides us with an important testimony recalling in his work a part of the famous Paragone, (comparison between the arts written by Leonardo where the privilege belongs to painting ), which did not converge in the Vatican Codex Urbinate lat. 1270 (manuscript compiled after Leonardo's death by his pupil and heir, Francesco Melzi). It is a praise of the plastic that Lomazzo himself acknowledges having drawn from Leonardo and which has been lost. Lomazzo's work should be considered as one of the main sources of reference that contributed to spreading Vinci's precepts in the field of painting, and this sixty-seven years before the publication of the editio princeps.