In 1653, he suggested that academicians should regularly give lectures (Conférences) on art theory, a practice which was adopted and became a corner stone of the institution's activities.
[2] Testelin's own lectures consisted of his reading of tables in which he summarised all the aspects of art theory his colleagues had previously presented.
He published these tables in 1680 as Sentimens des plus habiles peintres sur la pratique de la peinture et sculpture, mis en tables de préceptes, avec plusieurs discours académiques, ou conférences tenues en l'Académie royale des dits arts.
[5] In line with the increasingly intolerant religious policies of Louis XIV,[6] Testelin was dismissed from the Academy in 1681 because he was a protestant.
These are mostly scenes from the life of Alexander the Great and Louis XIV based on compositions by Le Brun and the battle painter Adam Frans van der Meulen.