Leon the Mathematician: the greatest scientist of Byzantium

Αποτέλεσμα εικόνας για Λέων ο Μαθηματικός: ο μεγαλύτερος επιστήμονας του Βυζαντίου

The great Byzantine scholar and “dean” of the Pandidakterion of Constantinople, Leon, was known in his age as Leon the Philosopher or Mathematician. He was born somewhere in Thessaly around 790 AD. He received his basic education in Andros, where he spent his childhood. He then studied grammar and philosophy in Constantinople. But his great love was science. So he returned to Andros and, under the guidance of a wise teacher – monk, he began his search for rare manuals on math and astronomy.
A chronographer of the age mentions the following about Leon’s thirst for knowledge: “While many admired him for his wisdom and for the way he reached the highest point of all the sciences, it is said that he (Leon) told a friend of his that he learned grammar and poetry while living in Constantinople and rhetoric and (physic) philosophy and the knowledge of numbers he obtained when he came to Andros. Because there, after meeting a wise man and learned the basics from him, because the quantity of knowledge he found did not satisfy him, he began visiting the monasteries and looking through the books they had and tried to obtain them. He then climbed mountaintops and with great care, after he studied the books, he was raised to the height of knowledge. When he was satisfied with learning, he returned to Constantinople and started sowing the seeds of science in the minds of those who wished it.” From the above we can easily come to the conclusion that many monasteries, even those in remote areas away from the capital, guarded rare scientific books in their libraries, and so became centers of attraction and meeting points of various educated Greeks, both clergy and civilians.
After his return to Constantinople in 835 AD, Leon worked as a private tutor, «μαϊστωρ» of the natural sciences. He lived a very modest life until his meeting with the then emperor Theofilos (829-843 AD). Leon, even though he was famed in the circles of the scholars of Constantinople, became famous by accident. A student of his that followed a military career was captured in a skirmish with Arab soldiers, and led to the prison of Baghdad, the capital of the powerful Caliphate of (Αββασιδών). There he managed to be accepted by the Caliph Al-Mamoon (nephew to the famous Caliph Harun Al Rasid, protagonist in the tale of a thousand and one nights). The Caliph was impressed by the mathematical knowledge of the young Greek that surpassed the Arab mathematicians at his court. After liberating the young soldier and made him a professor in the university of Baghdad, he inquired about the scientific level of the Byzantines. The Greek, after assuring him that there were thousands of young people learning science in the empire (showing that knowledge in Byzantium was available to quite a large number of civilians that wished it, irregardless of their social or financial situation, something inconceivalbe in the West), talked to him about Leon. Then Al-Mamoon, impressed, sent a letter to Leon with the young mathematician, asking about various mathematical problems, which Leon solved without any difficulty. Excited, the Caliph sent two more letters, one to Leon, asking him to come to Baghdad to teach, and another to Theofilos, asking him to allow Leon to come to the Caliphate, promising 2000 gold pieces and eternal piece, and ending with the following: “If this happens, all the Saracenes will bow before you and you will have so much wealth that human eyes never saw its like before!”. Theofilos, though, declined.

From then began Leon’s grand career. Theofilos funded him and allowed him to teach in the temple of Forty Martyrs. His lectures were given for free. In 840 AD, Leon is made a Metropolitan of Thessaloniki. In 843, though, he is quickly dismissed, as an iconoclast after the final restoration of icons, and he returns to Constantinople. There, with the full support of the empress Saint Theodora (who dismissed him from his post in Thessaloniki), her son emperor Michael C (The Drunk) and Caesar (prime-minister) Vardas, he re-establishes the Pandidakterion and in 855 AD he is made into “High Philosopher”, a kind of dean. Thousands of students flock to observe the free lessons Leon is giving (mathematics – algebra and geometry – astronomy and music, the “tetractis” of the Byzantines and later the “quadrivium” of the West). Among his students were big names of the “Macedonian Renaissance” (867-1081), like Fotios the Great, Arethas of Patras, Cyrill and Methodius, and the astronomer Theodigeos, his successor as dean of the Pandidakterion.
Leon’s work as a mathematician, astronomer and engineer was valuable. He was the first in the world to introduce letters instead of numbers in theoretical arithmetics and algebra (for example in equations) and not the Arabs (who introduced as arithmetic signs the indian numbers we use today). He rescued the writings of great Greek scientists like Apollonios, Pergaios, Theonas, the great Euclid – with explanatory comments, used widely in the West – Archimedes and Ptolemaios, and he took care of the transport of many of them to the Caliph’s court. He also made astronomical tables and corrected an error of the astronomer Porphyrius about the movement of the planets. Sadly, from his great work as an author nothing remains apart from the comments on Euclid, due to time and mostly due to the religious fanaticism of some iconolaters, that after the triumph of Orthodoxy and the perseverance of the worship of icons, destroyed his works after his death.
He was even more famous, though, for perfecting the ancient telecomunications system, the optical telegraph. It is known that since the antiquity, people used frictorian towers to warn each other about imminent raids. The frictorian “chains” though were only some decades of kilometers in length. Leon created a chain of only seven frictorian tower-stations, measuring approximately two thousand kilometers (!) from Constantinople to Tarsus of Cilicia, which he built on the tallest mountaintops between the two cities, so their fires would be visible from hundreds of kilometers away. The system transmitted not one but twelve different messages (for example raid, victory or defeat, enemies retreating, fire, earthquake, flood etc). That was possible thanks to two perfectly synchronized mechanical clocks (the first in history!) placed at the two ends of the frictorian chain, that functioned based on a division of the day in hours with 12 corresponding messages. With that system, the imperial headquarters in Constantinople could be informed about what was happening in the critically important eastern front, within eleven hours at the most. That speed of relaying messages through great distances was overcome only in the 19th century with the invention of the telegraph. Sadly, the system only functioned for a few decades, since when the Arabs conquered Tarsus they destroyed the mechanical clock.

Finally, Leon, having extensive knowledge on Alexandrian technology, created various metal “automatons” for the Byzantine palace, using hydrostatic and aerostatic pressure. One of those was a gold-plated tree with golden birds that moved their wings and sang on its branches, while on its top a golden angel played the trumpet. Under the tree, golden automated wine-pourers offered wine to the emperor’s guests. On the marble base of the throne, whenever someone approached, bronze gold-plated lions would stand, open their mouths and roar. Similar machines were created by Heron the Alexandrian for Ptolemy, while other automatons were in the byzantine palace and the court of the Arab Caliph to impress visitors.

The most impressing feat of Leon in automation was, according to the “Περί βασιλείου τάξεως” work of Constantine VII Porphyrogenitus (912-949) the “mechanical sweeper”, a mechanical turtle that cleaned the streets of Constantinople, maybe useful even to today’s street cleaners! All these impressive machines, according to the sources were destroyed by the Byzantines in times of financial hardships, either being melted for golden coins or discarded because they could not be repaired.



·  Ε. Λ. Μπουρδάκου : «Αρχαία ρομπότ», β΄ έκδοση, εκδόσεις «Ελεύθερη Σκέψις», Αθήνα, 2002.
·  P. Lemerle : «Ο πρώτος βυζαντινός Ουμανισμός», εκδ. Μορφωτικό Ίδρυμα Εθνικής Τραπέζης, Αθήνα, 1981.
· Β. Σπανδάτου κ.λ.π. : «Οι θετικοί επιστήμονες της Βυζαντινής Εποχής», εκδ. «Αίθρα», Αθήνα, 1996.

* Ο Δημήτριος Ντούρτας είναι Δικηγόρος Αθηνών και κάτοχος μεταπτυχιακού διπλώματος στον Τομέα  Ιστορίας, Φιλοσοφίας, Κοινωνιολογίας και Εκκλησιαστικού Δικαίου της Νομικής Σχολής του Πανεπιστημίου Αθηνών.


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