Let’s leave Jerusalem for a moment and take note of the burst of science and philosophy happening in Cordoba and Toledo at this time. Read more here about Maimonides, the Jewish scholar and physician who began his life in Andalusia and then became Saladin’s personal physician in Cairo.
During the time that Saladin was creating his empire in the east, a fierce sect of North Africans, the Almohads, had taken over most of western North Africa and much of Andalusia. They captured Seville in 1148 and Cordoba in 1149. They were battling back Christians in the north and the previous North African dynasty, the Almoravids, whom they pushed across the water to the Balearic Islands.
Normally, a North African conquest was not a big win for philosophy, but in this case, the second Almohad Caliph was a serious scholar. Abu Yakub Yusuf, ruling first from Marrakesh then from Seville after 1171, encouraged and protected scholars. This was important because for some time, there had been a power struggle between Muslims who believed that reason could grasp truth (and therefore favored scientific study) and those who considered elevation of reason a heresy against an unknowable Allah. The controversy began long before, under Abbasid Caliph al-Mamoun in the 9th century. In an empire that united church and state, the controversy put people in jeopardy of their lives.
But now, here in Cordoba, a new dynasty was choosing to suspend all such judgment and permit free thought and writing. Caliph Abu Yakub Yusuf also commissioned a statement of doctrine for Almohads, which was published in 1181. It began with the statement that, “It is by the necessity of reason that the existence of God, Praise Be To Him, is known.”
One of the scholars sheltered by the Caliph was Ibn Rushd, whose name passed to us via Spanish and Latin as “Averroes.” The Caliph and Ibn Rushd shared a love of Aristotle, whose works were not yet known in the Christian west but were widely available in Arabic. In 1179, Ibn Rushd was appointed Chief Judge in Seville and Cordoba, and he began writing a commentary on Aristotle. By 1195, when he fell out of favor after his Caliph’s death, he had written summaries, explanations, and original commentaries on all of Aristotle’s works except for The Politics, but also on Plato’s Republic. In the next century, Latin scholars translated his works and Aristotle’s, and Thomas Aquinas worked from those sources.
Averroes wrote his own philosophical works, and like all of the Muslim polymaths, he was also a physician who wrote summaries and commentaries of medical books. His work on the general principles of medicine was translated into Latin and became a standard textbook in Italian and French universities for the rest of the Middle Ages. In his original philosophical works, he argued for God’s existence with what we’d call an “Intelligent Design” argument.
Ibn Zuhr lived in Seville, the son of an aristocratic old Arab family. He became a physician, as had all of the men in his family for six generations. His life in Seville was interrupted by falling out of favor with the Almoravids, and he fled to Morocco, but when the Almohads conquered Seville, he moved back and began working again under the protection of Caliph Abu Yaqub Yusuf. He, too, wrote many books; his name came to us through Spanish and Latin as Avenzoar.
Ibn Zuhr, or Avenzoar, wrote a companion volume to Averroes’ medical textbook. Of course, both men worked from the idea that bodies must be balanced with food, hot with cold, dry with wet, for health. All medical science at this time was based on Aristotle’s “four humors.” But in Kitab al-Taysir, he also described the Scabies mite, the smallest animal that could be seen without magnification, which would not be available for several more centuries. He also reported that he had practiced and perfected some surgical techniques by operating on animals, like giving a goat a tracheotomy. In other work, he suggested plastic surgery for ungainly facial features. Perhaps most remarkably of all, his daughter and grand-daughter became obstetricians.
Ibn al-Baitar was born after Ibn Zuhr’s death, and near the end of Ibn Rushd’s life, but in the same intellectual environment that they had helped to shape. He lived in Malaga and studied botany. Botany was a branch of herbal medicine, so he was collecting plants and cataloging them as to their use. He studied plants all over Spain, then moved south into Morocco. He collected plants there, and worked his way across North Africa through Tunis, Algeria and Libya. He traveled to Constantinople and its nearby Antalya region. He ended up back in Cairo, serving Saladin’s successors as their Chief Physician and herbalist. When he followed Sultan al-Kamil to Damascus, he was able to study the plants of Palestine and Syria, too.
Ibn al-Baitar’s major work was, of course, an encyclopedia of herbs. It compiled in alphabetical order all of the herbs known to the ancients, as well as another 400 discovered by Muslim doctors. Each entry told what he knew about the plant, and then provided citations from older writers, both Greek and Arabic. His second major work was an encyclopedia of medicine, which drew heavily from his herbal work.
Probably near the end of his life, Ibn al-Baitar described a new chemical that he called “Chinese snow.” It was saltpeter, the earliest explosive gunpowder. He died in 1248, just before gunpowder began to be produced in Europe and the Middle East. In 1270, another Arabic writer (Hasan al-Rammah) described how to make and purify saltpeter. That’s how it all began.