To list all of Muhammad ibn Zakariyya’s accomplishments would fill a week’s worth of blog posts. So I’m going to confine myself to just two of them: First, he was the first person in history to recognize that measles and smallpox were different diseases, each with their own symptoms and treatments. And second, although we tend to think of psychology as something that began with Sigmund Freud at the dawn of the 20th Century, Muhammad ibn Zakariyya famously employed a psychological cure to free the Amir Mansur of Bukhara of a case of arthritis that was so severe, the Amir could barely move:
Another of the House of Saman, Amir Mansur ibn Nuh ibn Nasr, became afflicted with an ailment which grew chronic, and remained established, and the physicians were unable to cure it. So the Amir Mansur sent messengers to summon Muhammad ibn Zakariyya ar-Razi to treat him. Muhammad ibn Zakariyya came as far as the Oxus [River], but, when he reached its shores and saw it, he said, "I will not embark in the boat, for God Most High saith—'Do not cast yourselves into peril with your own hands;' and again it is surely a thing remote from wisdom voluntarily to place one's self in so hazardous a position." Ere the Amir's messenger had gone to Bukhara and returned, he had composed the Kitab-i-Mansuri [Book of Mansur], which he sent by the hand of that person, saying, "I am this book, and by this book thou canst attain thine object, so that there is no need of me."
When the book reached the Amir he was grievously afflicted, wherefore he sent a thousand dinars and one of his own private horses fully caparisoned, saying, "Show him every kindness, but, if this proves fruitless, bind his hands and feet, place him in the boat, and fetch him across." They did so, but their entreaties moved him not at all. Then they bound his hands and feet, placed him in the boat, and, when they had ferried him across the river, released his limbs. Then they brought the led-horse, fully caparisoned, before him, and he mounted in the best of humours, and set out for Bukhara. So they enquired of him, saying, "We feared lest, when we should cross the water and set thee free, thou wouldst cherish enmity against us, but thou didst not so, nor do we see thee annoyed or vexed in heart." He replied, "I know that every year twenty thousand persons cross the Oxus without being drowned, and that I too should probably not be drowned; still, it was possible that I might perish, and if this had happened they would have continued till the Resurrection to say, 'A foolish fellow was Muhammad ibn Zakariyya, in that, of his own free will he embarked in a boat and so was drowned.' So should I be one of those who deserve blame, not of those who are held excused."
When he reached Bukhara, the Amir came in and they saw one another and he began to treat him, exerting his powers to the utmost, but without relief to the patient. One day he came in before the Amir and said, "To-morrow I am going to try another method of treatment, but for the carrying out of it you will have to sacrifice such-and-such a horse and such-and-such a mule," the two being both animals noted for their speed, so that in one night they would go forty parasangs [132 miles].
So next day he took the Amir to the hot bath of Ju-yi-Muliydn, outside the palace, leaving that horse and mule ready equipped and tightly girt in the charge of his own servant at the door of the bath; while of the King's retinue and attendants he suffered not one to enter the bath. Then he brought the King into the middle chamber of the hot bath, and poured over him tepid water, after which he prepared a draught, tasted it, and gave it to him to drink. And he kept him there till such time as the humours in his joints had undergone coction.
Then he himself went out and put on his clothes, and, taking a knife in his hand, came in, and stood for a while reviling the King, saying, "O such-and-such, thou didst order thy people to bind and cast me into the boat and to threaten my life. If I do not destroy thee as a punishment for this, I am no true son of [my father] Zakariyya!"
The Amir was furious and rose from his place to his knees. Muhammad ibn Zakariyya drew a knife and threatened him yet more, until the Amir, partly from anger, partly from fear, completely rose to his feet. When Muhammad ibn Zakariyya saw the Amir on his feet, he turned round and went out from the bath and both he and his servant mounted, the one the horse, the other the mule, and turned their faces towards the Oxus. At the time of the afternoon prayer they crossed the river, and halted nowhere till they reached Merv. When Muhammad ibn Zakariyya alighted at Merv, he wrote a letter to the Amir, saying, "May the life of the King be prolonged in health of body and effective command! I your servant undertook the treatment and did all that was possible. There was, however, an extreme failure in the natural caloric, and the treatment of the disease by ordinary means would have been a protracted affair. I therefore abandoned it in favour of psychical treatment, carried you to the hot bath, administered a draught, and left you so long as to bring about a coction of the humours. Then I angered the King, so as to aid the natural caloric, and it gained strength until those humours, already softened, were dissolved. But henceforth it is not expedient that a meeting should take place between myself and the King."
Now after the Amir had risen to his feet and Muhammad ibn Zakariyya had gone out and ridden off, the Amir at once fainted. When he came to himself he went forth from the bath and called to his servants, saying, "Where has the physician gone?" They answered, "He came out from the bath, and mounted the horse, while his attendant mounted the mule, and went off."
Then the Amir knew what object he had had in view. So he came forth on his own feet from the hot bath; and tidings of this ran through the city. Then he gave audience, and his servants and retainers and people rejoiced greatly, and gave alms, and offered sacrifices, and held high festival. But they could not find the physician, seek him as they might. And on the seventh day Muhammad ibn Zakariyya's servant arrived, riding the mule and leading the horse, and presented the letter. The Amir read it, and was astonished, and excused him, and sent him an honorarium consisting of a horse fully caparisoned, cloak, turban and arms, and a slave-boy and a handmaiden, and further commanded that there should be assigned to him in Ray from the estates of al-Ma'mun a yearly allowance of two thousand dinars in gold and two hundred ass-loads of corn. This honorarium and pension-warrant he forwarded to him at Merv by the hand of a man of note. So the Amir completely regained his health, and Muhammad ibn Zakariyya attained his object.
From Nizami Arudi as-Samarqandi, Chahar Maqala (The Four Discourses), Edward G. Browne, tr., Mirza Muhammad, ed., London:Luzac & Co., 1921, pp. 83-85.
Michael Isenberg writes about the Muslim world, medieval and modern. His forthcoming novel, The Thread of Reason, is a murder mystery that takes place in Baghdad in the year 1092 and depicts the battle for the Muslim soul between those who embrace science and tolerance, and those who would throw in their lot with mysticism and persecution instead.