Alchemy has also played a role in the evolution of paint. Alchemists and pigment manufacture intersect as early as the Leyden papyrus X and Stockholm papyrus, and as late as Robert Boyle's Origin of Formes and Qualities (1666). The pigment recipes of artists such as Cennino Cennini and Theophilus have been influenced by both the practical and theoretical aspects of alchemy, and contained some allegorical and magical elements.[4]