[In memory of Galen--on the 1800th anniversary of his death].

In the year 1999 or 2000 it is the 1800th anniversary of Galen's death. He was one of the leading thinkers in medicine and one of the best known physicians of all times. He was not only a gifted practitioner but also a first class anatomist, physiologist, pathologist, and pharmacologist of the ancient times. His work is present in all these parts of medicine. This article gives Galen's biography and contributions to the above mentioned medical disciplines and practice. During fourteen centuries Galen's works were undisputable textbooks for students of medicine and most valuable manuals for practitioners besides the works of Hippocrates. Galen founded a new medico-philosophical school, based on that of Hippocrates, but comprising all medical knowledge of that time as well as his remarkable medical experience. While Hippocrates formulated the basis of the clinical medicine and the members of the Alexandria school made the most important discoveries in anatomy and physiology, Galen compiled all the knowledge of his predecessors, added a philosophical basis and created a unified system for centuries believed to be a definitive one where nothing should be added. Besides Hippocrates, Galen was the most outstanding physician of the ancient times and one of the greatest of all times. He established the fundamentals of the medical science which are still significant.