The pancreas was generally ignored in antiquity, both as an organ and as a seat of disease. The first description of the pancreas is attributed to Herophilus. It was in the 17th century that the main duct of the organ was described and its significance demonstrated. At that time, Brunner thought that the pancreas was not essential to digestion, and he failed to associate the pancreas with diabetes. Claude Bernard discovered the function of the pancreas in digestion. In 1922, Banting and Best obtained isletin and demonstrated the capacity of the substance to cause a dog to recover from diabetic coma. In 1889, Reginald Fitz firmly established pancreatitis as a disease entity. In 1927, the first case of hyperinsulinism due to a tumor of the islet cells was reported. Twenty-eight years later, Zollinger and Ellison described two patients with unusually severe peptic ulcer disease, both of whom had noninsulin-secreting tumors of the pancreatic islets. Subsequently, gastrin was isolated as the hormone responsible for this syndrome. In March 1940, Dr. O. Whipple performed the first recorded one-stage pancreaticoduodenectomy. Much progress has been made since then and today transplantation of isolated islets and portions of whole pancreas is a reality.