Galen, a Greek physician and philosopher born around 129 AD and passing away circa 210 AD, is renowned for his discovery of blood in human arteries and his detailed study of the human nervous system, particularly the nerves serving the head, face, and upper chest. As the son of Nicon, a prosperous architect and builder in Pergamum (now part of modern-day Turkey), Galen had a wealth of opportunities before him. Initially, he pursued philosophy, a customary path for someone of his upbringing. However, after Nicon dreamt of Asclepius, the god of healing, advising him to let Galen study medicine, Galen began his medical education in Pergamum at 16 or 17. His pursuit of medical knowledge took him across the eastern Mediterranean, where he studied in various cities, including Smyrna (present-day Izmir, Turkey) and Corinth (Greece), before completing his studies in Alexandria, Egypt.Upon returning to Pergamum, Galen, at 28, became the physician to a school of gladiators, a position he held for four years, earning him the title of the "first sports medicine specialist." His career then led him to Rome at the age of 32, where he gained fame and influence as a physician, often taking on complex cases that others could not manage. He served as a consultant's consultant and traveled with the Roman legions of Marcus Aurelius, acting as the personal physician to several emperors.Galen conducted dissections of both animals and humans, meticulously documenting his observations—a practice not common at the time. He identified seven of the twelve cranial nerves and conducted experiments such as cutting nerves to observe the outcomes, earning him recognition as "the founder of experimental medicine."Remarkably, Galen was the first to assert that arteries carried blood, not air—a belief that had persisted for over 400 years within the Alexandrian school of medicine. Despite this breakthrough, his theories on blood circulation were inaccurate, a misconception that would not be corrected until the 17th century by the English physician William Harvey.Alongside Hippocrates, who preceded him by around 500 years, Galen was among the most esteemed physicians of antiquity. He absorbed all available medical knowledge of his era, compiled it, and wrote extensively and eloquently about it. While Galen encapsulated the medical understanding of ancient times, his writings, revered for over a millennium, stifled medical advancement—a situation Galen himself would have strongly opposed.
