In the 17th century, several collections of medical case reports were published in the Netherlands, mostly by surgeons. The often detailed descriptions provide a good impression of medical practice in those days. One of the best-known authors of such a collection of case reports is doctor Nicolaes Tulp (1593-1674). In the latest edition of his Observationes medicae (1739), 229 cases are described, seven of which pertain to traumatic skull and brain injury. These cases provide a clear picture of the treatment of traumatic brain injury in Amsterdam in the 17th century. The cases were caused by falling objects, a fall due to drunkenness, a gunshot wound and a fall on a slippery bridge. The frequency of surgical intervention in traumatic brain injury as reported by Tulp is remarkable; he describes frequent trepanation and craniectomy for epidural and acute subdural haematoma, coagulation of bleeding vessels on the dura, removal of contused brain tissue and the operative treatment of depressed skull fractures. It may be further concluded from the descriptions that Tulp adhered to a large extent to the medical views concerning the blood circulation as described by Galenus (129-199 AD).