Galen

Galen of Pergamon was a Greek physician, surgeon and philosopher of the Roman Empire who served as doctor to several emperors in the 2nd century. Through experiment, dissection and an enormous body of writing, he built a system of anatomy and medicine that dominated medical thought in Europe, Byzantium and the Islamic world for well over a thousand years.

Galen was born in September 129 in Pergamon, in the Roman province of Asia, now Bergama in Turkey. His father, Aelius Nicon, was a wealthy architect with wide intellectual interests who gave his son a broad education in the main philosophical schools of the day. Pergamon was then a major cultural centre with a great library and a temple of the healing god Asclepius. Galen says that around 145 his father dreamed that Asclepius ordered the boy to study medicine.

At 16 Galen began four years as an attendant at the local Asclepius sanctuary. His father died in 148, leaving him rich, and he spent the following years travelling to study at Smyrna, Corinth, Crete, Cyprus and finally Alexandria, the leading medical school of the age. In 157 he returned home as physician to the gladiators kept by the high priest of Asia. Treating their injuries, which he called windows into the body, taught him a great deal about living anatomy, and he claimed that only five gladiators died during his time in the post, against sixty under his predecessor.

Galen moved to Rome in 162 and quickly made a name through public demonstrations and successful cures. His combative manner made enemies among other doctors, and fearing exile or poisoning he left the city for a time. In 169 the emperor Marcus Aurelius summoned him back as a great epidemic, the Antonine Plague, spread through the empire. Galen described its symptoms in scattered passages, and his account is detailed enough for modern scholars to identify the disease as related to smallpox.

Marcus released him from accompanying the army to the northern frontier, and Galen stayed in Rome as physician to the young heir Commodus. He later attended Septimius Severus as well.

Since Roman law forbade dissecting human bodies, Galen worked on animals, especially Barbary apes and pigs, and assumed their anatomy closely matched ours. In public experiments he showed that tying off a nerve silenced a squealing pig, proving that the voice is controlled by the brain through nerves. He distinguished motor from sensory nerves, described the spinal cord, and noted the difference between dark venous and bright arterial blood.

His physiology rested on the theory of four humours inherited from the Hippocratic writers: blood, yellow bile, black bile and phlegm, whose balance determined health and temperament. He held that blood was made in the liver and passed through tiny pores in the wall of the heart, ideas later shown to be mistaken.

In Galen's view the ideal physician must also be a philosopher, and he wrote on logic and philosophy as well as medicine. His output was vast; the surviving works alone run to some three million words, thought to be less than a third of what he wrote.

The date of his death is uncertain. A medieval Byzantine lexicon has him dying at 70, around 199, but Arabic sources say he died at 87, which would place his death around 216, and several modern scholars favour that later date.

After the fall of the western empire, Galen's works survived mainly in the Byzantine Empire. From the 8th century Syriac and Arabic translations, notably by Hunayn ibn Ishaq, made him a central authority in Islamic medicine, where physicians such as al-Razi and Ibn al-Nafis both built on and challenged him. Latin translations from the Arabic spread his system through medieval European universities. Only in the 16th century did Andreas Vesalius, dissecting human bodies, show that many of Galen's descriptions applied to apes rather than people.

Galen lived at the height of the Roman Empire. Our 100 and 200 maps show the empire that stretched from his native Pergamon to Rome and Alexandria.