It seems remarkable that a brain structure as prominent as what we call the Sylvian fissure was not named until the 17th century. It was described by Franciscus de la Boë (whose name was latinized to Sylvius) and his portrait can be seen spanning his eponymous fissure. The engraving of the brain is taken from Caspar Bartholin’s Institutiones Anatomicae which was published in 1641. Sylvius also described the narrow passage between the third and fourth ventricles, subsequently called the aqueduct of Sylvius. He carried out most of his anatomical studies in Leiden, although he was German by birth. He occupied the chair of medicine at Leiden, and his successor was Boerhaave. Sylvius integrated anatomy with the developing knowledge of chemistry to found the iatrochemical approach to medicine: bodily processes both in health and disease were attributed to chemical actions. According to some scholars, Sylvius was also the inventor of genever (gin) which was used for medical purposes.