Galen was born in AD 129 at Pergamum, a culturally Greek city near the north-west coast of Roman Asia, in what is now Turkey; his father was an architect.1 His name comes from the Greek adjective γαληνός, “calm”,2 which the great Greek dictionary of Liddell, Scott and Jones explains as “calm, esp. of the sea” and, of people, “gentle”.3 It hardly fits. Galen became doctor to gladiators and to emperors, one of the most prolific writers of the ancient world, and one of its most combative.1
From the gladiators to the palace
His father meant him for philosophy or public life, but in 144 or 145, Galen says, the healing god Asclepius told his father in a dream to let the boy study medicine.4 Galen puts it in one line: «εἶθ' ὕστερον τοῦ πατρὸς ὀνείρασιν ἐναργέσι προτραπέντος ἐπὶ τὴν τῆς ἰατρικῆς ἄσκησιν ἀφικόμεθα», “then later, my father being urged on by vivid dreams, I came to the practice of medicine” (our translation).5 When his father died, in 148 or 149, Galen was nineteen, rich and free, and he went to study at Smyrna, Corinth and Alexandria.1,4
In 157 he came home to a coveted post: doctor to the gladiators of Pergamum.1,4 In a book on drugs he tells how the high priest of the city put the gladiators in his care alone, «καίτοι νέῳ τὴν ἡλικίαν ὄντι. τοῦ γὰρ ἐνάτου καὶ εἰκοστοῦ ἔτους ἠρχόμην», “though I was young: I was just beginning my twenty-ninth year” (our translation). Many wounded men had died in the years before, he says, but none of his patients died, so four more high priests in turn kept him on.6
In the early 160s he moved to Rome,1,2 where his lectures and dissections soon made him famous.1 Fame brought enemies. In 166 he slipped away, letting it be thought that he was going to Campania, and sailed home;4,7 one account says he feared that rival doctors would have him exiled or poisoned.2 That year the great epidemic now called the Antonine Plague, or the Plague of Galen, reached Rome.8
Two years later the emperors Marcus Aurelius and Lucius Verus summoned him to their winter quarters at Aquileia.4,7 Lucius died that winter, and Marcus wanted Galen with him on his war against the Germans, but Galen persuaded him to leave him in Rome to look after his young son Commodus.7 While Marcus was away, from 169 to 176, Galen wrote up many of his major works:1 «πολλὰς πραγματείας ἔγραψα φιλοσόφους τε καὶ ἰατρικὰς», “I wrote many treatises, philosophical and medical” (our translation).7 By his own account the emperor used to call him «τῶν μὲν ἰατρῶν πρῶτον εἶναι, τῶν δὲ φιλοσόφων μόνον», “first among doctors, and alone among philosophers” (our translation).2,9
He went on to serve Commodus and Septimius Severus.1,2 In 192 a fire destroyed the Temple of Peace in Rome, and with it a storehouse in which Galen kept books, drugs and instruments:1,10,11 in his words, «τὸ τῆς Εἰρήνης τέμενος ὅλον ἐκαύθη, καὶ κατὰ τὸ παλάτιον αἱ μεγάλαι βιβλιοθῆκαι», “the whole precinct of Peace burned down, and the great libraries on the Palatine” (our translation).11 One account dates the fire to 191.4
Debated among scholars Nobody knows when he died. The Byzantine lexicon called the Suda has him die at seventy, about 199; Arabic sources say at eighty-seven, about 216, the date Vivian Nutton and Véronique Boudon-Millot favour.2 The Stanford Encyclopedia of Philosophy keeps the traditional date, about 200, but notes later sources that have him alive more than ten years after that.1
A mountain of books
Galen may have written more than any other ancient author.2 The standard edition of his Greek, by Karl Gottlob Kühn (Leipzig, 1821–33), runs to some twenty thick volumes,1,12 and what survives has been put at over 2.6 million words, or at more than 4 million.1,13 Véronique Boudon reckons his works at an eighth of all Greek literature from Homer to the end of the second century AD.12
Even so, much is lost. Much of his philosophy went: he lists more than twenty-five works on ethics, of which only two survive whole, and nearly all his books on logic are gone.1 Some works survive only in translation: the last six books of Anatomical Procedures only in Arabic, the Outline of Empiricism only in medieval Latin.12,13,14 And some books that carry his name are not his. The Introduction, or the Physician and the Medical Definitions came down among his works, but the Corpus Medicorum Graecorum's list puts them in square brackets, as not his,14 and the reader files the Introduction under Pseudo-Galen.15 The trouble began in his lifetime. In On My Own Books, his guide to his genuine works, he tells how a man of letters in the booksellers' quarter of Rome read two lines of a book sold as Galen's and tore up its title: “This is not Galen's language—the title is false” (P. N. Singer's translation).10,16
Reading Galen
Galen writes the Greek of his own day, and says so. He has little patience with the people he calls Atticizers, who insisted on the old words of classical Athens: teaching clearly, he says, matters more.17 In a commentary on Hippocrates he tells his readers to call a kind of plaster what they like: «οὐ γὰρ ἀττικίζειν διδάσκειν πρόκειταί μοι τοὺς νέους ἐν τοῖσδε τοῖς ὑπομνήμασιν», “for my task in these notes is not to teach the young to talk Attic” (our translation).18 Yet words fascinated him: among the books lost in the fire were his word-books, including a lexicon of medical words in Old Comedy, the comic plays of classical Athens.19
His voice is unmistakable, argumentative and much given to digression. He makes his case by attacking his rivals and by explaining his heroes, Plato and Hippocrates.1 That the Best Physician Is Also a Philosopher opens with a jab at doctors who, like athletes longing for an Olympic win without training for it, «ἐπαινοῦσι μὲν γὰρ Ἱπποκράτην, καὶ πρῶτον ἁπάντων ἡγοῦνται», “praise Hippocrates and think him the first of all” (our translation), and then do anything but follow him.20 His fiercest words are for the medical sects. Of the followers of Asclepiades, who would not grant that the kidneys make urine, he writes: «δυσαπότριπτόν τι κακόν ἐστιν ἡ περὶ τὰς αἱρέσεις φιλοτιμία καὶ δυσέκνιπτον ἐν τοῖς μάλιστα καὶ ψώρας ἁπάσης δυσιατότερον», in Arthur Brock's translation “so difficult an evil to get rid of is this sectarian partizanship … harder to heal than any itch”.21
His medicine in plain words
Galen took over the theory of the four humours, the body's fluids: blood, yellow bile, black bile and phlegm. He tied an excess of each to a temperament: sanguine, choleric, melancholic or phlegmatic.2 He pictured the body as three linked systems: the brain and nerves, for thought and sensation; the heart and arteries, for life-giving energy; and the liver and veins, for nutrition and growth. Dissecting human bodies was forbidden in his day, so he worked on animals, above all apes, and also pigs, often while they were alive.2 In a famous experiment he tied the spinal cord of a live pig to show that the brain is the seat of the soul's ruling part.1 To prove that urine comes from the kidneys, he says, tie off the ureters, the tubes from the kidneys to the bladder, in a living animal: later you will find “the bladder empty and the ureters quite full and distended”.21
Behind it all lay one conviction: «μηδὲν ὑπὸ τῆς φύσεως γίγνεσθαι μάτην», “nothing is done by Nature in vain”.22 His great work On the Usefulness of the Parts sets out to show that every part of the body was purposely, indeed divinely, made for its job.1 The same conviction could lead him astray. Some blood, he argued, passes through the wall between the two sides of the heart: «ἐκ τῆς δεξιᾶς κοιλίας εἰς τὴν ἀριστερὰν ἕλκεται τὸ λεπτότατον ἔχοντός τινα τρήματα τοῦ μέσου διαφράγματος αὐτῶν», “the thinnest portion of the blood is drawn from the right ventricle into the left, owing to there being perforations in the septum between them”, though he admits that “it is not possible, however, actually to observe their extreme terminations”.22 In the sixteenth century the anatomist Andreas Vesalius showed that the wall is not pierced at all.2
Why he matters
Galen's views dominated Western medicine for more than 1,300 years.2 In ninth-century Baghdad Hunayn ibn Ishaq (808–873) is credited with translating 129 of his works,2,23 and doctors writing in Arabic, such as al-Razi, author of Doubts on Galen, built on him and argued with him. In the Latin West, which recovered him from the eleventh century on through translations from the Arabic, he became the “Medical Pope of the Middle Ages”. Then, in 1543, Vesalius' De humani corporis fabrica corrected his anatomy from human dissection, and the work of William Harvey and others on the circulation of the blood carried knowledge beyond where Galen had left it; yet his advice to let blood for many illnesses stayed influential until well into the nineteenth century.2 After the Scientific Revolution the intellectual world largely ignored him. In recent decades scholars have come back to him, for his logic, his ethics and his thinking about mind and body.1