THE SIGNIFICANCE OF GALEN
for Medieval English Medicine

Galen's influence on medieval medicine in England was MASSIVE and lasted into the 17th century. 

Islamic scholars ‘saved’ ancient Greek medical knowledge, by translating works by Hippocrates and Galen into Arabic.  Galen’s works then entered western Europe through Arabic-to-Latin translations made in Spain and Italy.  This was HUGELY important in bringing western European medicine out of the ‘Dark Ages’. 

Christianity was important in the acceptance of the authority of Galen, because he believed in one God, which pleased the Church; this was important in ensuring the primacy of Galen in medieval medical teaching.  HOWEVER, the reverence for Galen’s authority discouraged original observation.  Medical learning became about memorising his texts rather than testing ideas through experimentation.  Galen therefore became a major factor slowing progress in medical ideas.

At Oxford University, Galen’s books were a crucial part of the core curriculum, which included also Hippocrates, the Book of Fevers, the Antidotarium of Nicholas of Salerno, and the Ars Medicineae (a compendium including numerous extracts from Galen). 

Galen did not go unchallenged in Islamic medicine:

  •   Rhazes’ (9th century) wrote a book: Doubts about Galen. 

  •   Ibn al-Nafis (13th century) realised that the heart circulated blood round the body (contradicting Galen) and disproved Galen’s theory that the liver created all the blood in the body. 

  •   Abd al-Latif al-Bagh (12th century) proved that the jaw was a single bone, not two (contradicting Galen)

However, few western European doctors challenged the authority of Hippocrates and Galen, or tried to develop or test new ideas (the 13th century surgeon Henri de Mondeville was a rare exception). 

PHYSIOLOGY

  •   The theories and teachings of Hippocrates and Galen – especially the Theory of the Four Humours – formed the basis of medieval Western European medical knowledge, and were key texts on university courses for a thousand years. 

  •   Hippocrates and Galen were simply incorporated (mistakes and all) into a huge often-contradictory body of information and doctors picked and chose as they wanted. 

  •   Errors in Galen (for instance the idea that the brain was the location of the soul) went unchallenged in England for centuries.

PATHOLOGY

  •   The foundation of Hippocratic methods and treatments was the Theory of the Four Humours.  Galen expanded on Hippocrates' theory, proposing that an imbalance of the four humours (blood, phlegm, yellow bile, and black bile) caused illness.  These ideas therefore became foundational in medieval English medicine – not just for physicians but in folk medicine – and still have echoes today (eg ‘feed a cold and starve a fever’). 

  •   Nobody today knows what ‘black bile’ was, but generations of doctors knew what they were looking for, and Galen wrote a book on how to recognise it. 

  •   Galen propounded the theory of opposites, clinical observation, and the idea that ‘bad air’ caused disease.  These (therefore) became key features of medieval English pathology. 

  •   Galen’s advocacy of urine analysis became (therefore) a key aspect of diagnosis. 

TREATMENT

  •   Galen’s emphasis on the use of opposites, bloodletting and herbal remedies ensured that these were used by English physicians.  He suggested that there was a connection between the appearance and properties of plants and their medicinal uses which was developed into the doctrine of signatures. 

ANATOMY & SURGERY

  •   Galen advocated dissections, but no dissections were done in England before 1500. 

  •   Many of Galen’s anatomical observations came from his dissections of pigs; but because he assumed the human body was the same, his books contained a number of errors … all of which were accepted on authority by English physicians. 

  •   Illustrations in Galenic texts were sometimes misleading. 

  •   Bodies were dissected in European universities as a visual aid whilst the Master read (usually) from Galen; it was a procedure to help the students understand Galen's books, not to advance their practical anatomical knowledge.  Medieval physicians believed Galen even when the evidence of their eyes told them otherwise.