Galen

Galen, also known as Aelius or Claudius Galenus and often called Galen of Pergamon, was a physician, surgeon, and philosopher of both Roman and Greek heritage. He is regarded as one of antiquity's most accomplished medical researchers, and his work shaped fields like anatomy, physiology, pathology, pharmacology, neurology, philosophy, and logic. For over 1,300 years, his ideas were the foundation of Western medical science.

Born in September 129 CE in Pergamon (modern-day Bergama, Turkey), Galen was the son of Aelius Nicon, a wealthy Greek architect with interests in philosophy, mathematics, logic, astronomy, agriculture, and literature. His father, described by Galen as kind and just, gave him a broad education. At 14, Galen encountered Stoic and Platonic philosophers in Pergamon, a major cultural hub with a library second only to Alexandria's and a large temple to the healing god Asclepius. His studies also covered Aristotelian and Epicurean thought. His father initially planned a career in philosophy or politics, but around 145 CE, a dream from Asclepius instructed Nicon to send his son to study medicine.

At 16, Galen began a four-year stint as a therapeutes (attendant) at the local asclepeion, a healing temple that functioned like a spa or sanitorium. There, he learned from figures like Aeschrion, Stratonicus, and Satyrus. After his father died in 148 CE, leaving him financially independent at 19, Galen traveled widely—to Smyrna, Corinth, Crete, Cilicia, Cyprus, and the renowned medical school in Alexandria—to study different medical theories. In 157 CE, at age 28, he returned to Pergamon as physician to the gladiators of the High Priest of Asia. He claimed he got the job by eviscerating an ape and, when other doctors refused to repair it, performing the surgery himself, thereby winning the High Priest's favor.

Galen's medical thinking was rooted in the Hippocratic theory of four humors: black bile, yellow bile, blood, and phlegm. Because human dissection and vivisection were banned in the Roman Empire by his time—though practiced earlier in Alexandria under Ptolemaic rule—Galen based his anatomical work mainly on Barbary apes. He later switched to pigs after noticing the apes' vivid facial expressions, which risked legal trouble. Aristotle had used pigs centuries before. Galen believed animal anatomy closely matched human anatomy and urged his students to examine dead gladiators or washed-up bodies to learn more.

His circulatory system theory stood unchallenged until Ibn al-Nafis described pulmonary circulation in his commentary on Avicenna's Canon. Galen's anatomical reports held until 1543, when Andreas Vesalius's *De humani corporis fabrica* published detailed human dissections, adapting Galen's physiology to the new findings. Galen considered himself both a physician and a philosopher, arguing in his treatise *That the Best Physician Is Also a Philosopher* that direct observation, dissection, and vivisection bridged the rationalist and empiricist medical sects. Many of his works survive in Greek or translation, though some were destroyed and others are likely misattributed. He died at age 70 or older, though the exact date is debated.

Galen's Greek name derives from the word for "calm," and his Latin names (Aelius or Claudius) indicate Roman citizenship. In his work *On the Affections of the Mind*, he described his early life and his father's character. Pergamon, his birthplace, was a center of learning and healing, attracting notable figures like the historian Claudius Charax, the orator Aelius Aristides, the sophist Polemo, and the consul Cuspius Rufinus.