The new exhibition opening in The Ritman Library on January 6th 2015 presents the iconography as it has developed around Hermes Trismegistus and the attributes that can be associated with him, such as the armillary sphere, the Tabula smaragdina, the ouroboros and the caduceus. Master of Change. Images of Hermes Trismegistus is based on works in the collection of The Ritman Library: printed books and manuscripts and prints ranging mainly from the early sixteenth to the late eighteenth centuries which show some facets of the philosopher-god who already in his first manifestation as the god Thoth in ancient Egypt was regarded as a ‘many-sided’ god. When Hermes eventually changed into the ‘patron saint’ of alchemy, he came to symbolize Mercury, a volatile metal which can form amalgams with almost all other metals. Mercury is also the beginning and end of the alchemical process and synonymous with the Philosophers’ Stone: ‘Est in Mercurio quidquid quaerunt sapientes’ – whatever the sages seek is in Mercurius.