Claudius Galen – The Man Who Laid the Foundations of Western Medicine

Biography
Full name: Aelius/Claudius Galenus

Born – died: c. 129 – c. 216 AD

Place of birth: Pergamon (present-day Bergama, Türkiye)

Occupation: Physician, anatomist, philosopher

Served under: Personal physician to the Roman Emperor Marcus Aurelius

Galen was born into a wealthy family and received a formal education. He began studying medicine at the age of 16, and later pursued his studies at renowned medical centers in Smyrna, Corinth, and especially Alexandria—the greatest center of knowledge of that time.

Medical Contributions

1. Anatomy and Physiology
Because human dissection was restricted, Galen relied mainly on animal dissections, especially monkeys and pigs. Even so, he accurately described many anatomical structures such as nerves, kidneys, the brain, and the circulatory system.

Notably, Galen was the first to demonstrate that:

• The brain, not the heart, is the center of emotion and thought.

• Blood vessels contain blood, not air, as was commonly believed at the time.

However, he also held some mistaken views—for example, he believed that blood was produced in the liver and circulated through two separate systems rather than in a closed loop.

2. The Theory of the Humors (Humorism)
Galen inherited and further developed Hippocrates’ theory of the “four humors”: blood, phlegm, yellow bile, and black bile. He believed that health depended on the balance among these four humors. Although this theory is now outdated, it served as the foundation for diagnosis and treatment for many centuries.

3. Pharmacology and Treatment
Galen was also well known for compounding medicines, with hundreds of remedies for common illnesses. “Galenic medicine” is the term used for traditional preparations made from herbs and natural ingredients according to his methods.

Legacy
About 500 works by Galen were transmitted, although only some of them survive intact. Later Arabic and Latin translations became core teaching materials in medical schools across Europe and the Islamic world from the 9th to the 16th centuries.

Galen’s influence only began to decline when scientists such as Andreas Vesalius, William Harvey, and other Renaissance anatomists started to question and prove many errors in his medical model.

Conclusion
Despite the limitations of his era, Claudius Galen is still regarded as one of the “pillars” of ancient medicine. His logical thinking, spirit of observation, and methodology paved the way for the later development of scientific medicine.

“Medicine is not only a skill, but also a philosophy of life.” – Claudius Galen