Physician, Philosopher, Astronomer, Physicist (129 – 216)

For some, he is the Father of Anatomy, for others he is the Father of Experimental Physiology and for others he is honoured as the Father of General Pathology. Undisputedly, however, Claudius Galen was the greatest physician of antiquity next to Hippocrates himself, as well as his spiritual successor. He was the physician who dominated the whole Oecumen for 1500 years. His massive work of monumental proportions, which has been translated into numerous ancient and modern languages, spans the fields of philosophy, physics, logic, astronomy, music, ethics and most importantly medicine.

Galen was born in Pergamum as the son of Nicon, a geometrist, architect, astronomer, renowned for his prudence. Galen studied philosophy and medicine for many years, first travelling to Smyrna, and then to Corinth, Cilicia, Phoenicia, Palestine, Lemnos, Scyros, Crete and Cyprus until arriving in Alexandria, the most illustrious spiritual center of humanity. There he enriched his knowledge on anatomy. He practiced his knowledge on orthopedics and surgery by treating the athletes and gladiators in Pergamum. When he came to Rome, he rose to fame thanks to his surgical skills and pharmacological knowledge. Galen returned to Pergamum for some time, only to return to Italy after an invitation from Marcus Aurelius. He created one of the most perfect medical systems, which dominated the medical world until the Renaissance.

As the quintessence of the philosopher-doctor, Galen estimated that philosophy was a prerequisite for medicine. His philosophy was that the doctor ought to be a philosopher, because philosophy is the science of truth, and medicine cannot exist without truth. Ethics were another important aspect of the philosopher-doctor, as he was obliged to practice medicine not for the honours, the money or the politics. Moreover, Galen expanded the work of Aristotle and Theophrastus in Logic as well as metaphysics. He was called the “first servant of nature”.

Three basic principles summarize Galen’s medical philosophy, which he himself expressed: First, that it is impossible to understand the nature of the disease without proper knowledge of the function and construction of the human body. Second, that there is no organ in the human body without a purpose. Third, that aging, even though an unstoppable process, it can be delayed.

Galen’s philosophy on biology concerned the existence of 3 classes, which comprised the living bodies: solids, humors and spirits. Wind, water, fire and earth represented the four elements which comprised each category and to each of them befall an equal amount of drastic elements: warmth, cold, wetness and dryness. From their mixture are produced the 4 humors of the human body: blood, phlegm, yellow bile and black bile. Spirits are 3 types: vital, living and animalistic. From these entities derive 3 forces which govern the living beings: the instincts (ἐπιθυμητική), which reside in the liver, the emotions (θυμοειδής) which reside in the heart and logic (λογική) which is found in the brain. For Galen, the physiological equilibrium of all four humours and the harmonic interplay between the three forces determine the requirements of a healthy life. If this equilibrium is not met, then disease will ensue.

Galen made pioneering discoveries in Anatomy and Physiology. He made important discoveries in myology, first describing the muscles of mastication, the brachium, the muscles of the chest and the hamstring muscles as well as the muscles of the larynx. He described the structure of the heart, discovered the ductus arteriosus and the fact that the arteries begin from the heart. His most groundbreaking discovery, however, came from the study of the circulatory and respiratory systems and was the existence of the capillaries, 1559 years before their “official” discovery by Marcelo Malpighi. First demonstrated that the nerves are controlled by the brain and discerned them between motor and sensory, described nervus vagus, the layers of the eyeball, the chiasma opticum and the physiology of vision. Galen was also a revolutionary surgeon, achieving widespread acclaim for treating patients successfully without pain. He did general surgeries, orthopedic surgeries, pleurectomies, tooth extractions, amputations, gastrorrhaphies and nasal polyp removal.

Furthermore, the great physician made extraordinary contributions in General and Special Pathology. In his books he describes with complete accuracy pleuritis, tuberculosis, pneumonia, lung cancer and lung abscess, liver diseases, diabetes, appendicitis, icterus, colics, neural paralysis, epilepsy, filariasis, gangrene, lithiasis and erysipelas. He had profound knowledge on the circulatory system, as well as on heredity, contagiousness, psoriasis, toxins, immunity and chronic diseases. He distinguished pathognomic signs from non-pathognomic. Other fields of medicine which Galen expanded were embryology, obstetrics and gynaecology, urology, andrology, orthopaedics, dermatology, tropical medicine and infectious diseases, pharmacology, homeopathy, clinical nutrition and hygiene.

Galen was said to be guided by Asclepius in his dreams. He had enormous respect for Hippocrates, whom he referred to as “Divine” and “Hegemon of all the good arts”. Nevertheless, his great admiration towards him was not based on dogmatism as the well-known phrase says “Hippocrates says yes, Galen says no.” Galen’s works, which consisted of 125 medical and 115 non-medical – philosophical or mathematicoastronomical ones, were the mainstay resources for learning medicine in the Western world until the Renaissance or early 19th century. During all these 1500 years, all medical treatises that were written were repetitive rehashes either of Hippocrates or Galen.


  1. “Galenos”. Helios New Encyclopaedic Dictionary. Passas, I. Athens, 1946. Print.
  2. Tziropoulou – Eustathiou, Anna. O en te leksei Logos. Georgiades: Athens, 2009. Print.

One thought on “Galen

Comments are closed.