Byzantine Culture

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Byzantine Science and Technology

Byzantium preserved Greek science, taught it, and occasionally advanced it. Astronomy, mathematics, mechanics, the beacon telegraph, the automata of the palace and the transmission to Islam and the west.

The standard verdict on Byzantine science is that it preserved rather than advanced: that a thousand years of scholars copied Euclid, commented on Ptolemy, taught Aristotle and added nothing. The verdict is roughly right as a summary of theoretical achievement and seriously misleading about what was actually going on.

Byzantium maintained an unbroken tradition of mathematical and astronomical teaching for eleven centuries, in a period when such teaching lapsed entirely in western Europe. It transmitted the whole corpus of Greek science to the Islamic world and then to the Latin west, twice. And in engineering — hydraulics, fortification, military technology, architecture — it was consistently inventive.

Mathematics and Astronomy

The tradition ran continuously from late antiquity. Its notable figures:

Hypatia of Alexandria (d. 415), who edited and commented on Diophantus, Apollonius and Ptolemy, and whose murder by a Christian mob has made her a symbol in arguments she would not have recognised.

Anthemius of Tralles and Isidore of Miletus (6th c.), the architects of Hagia Sophia, who were mathematicians first. Anthemius wrote on conic sections and burning mirrors; Isidore edited Archimedes and Eutocius.

Leo the Mathematician (9th c.), who taught at the school of the Magnaura in Constantinople, is credited with applying letters as symbols in algebraic contexts, and designed the beacon telegraph described below. The caliph al-Ma’mun is said to have tried to hire him away, which — whether or not it happened — reflects a real Byzantine reputation.

Maximos Planoudes (13th c.), who introduced Arabic numerals and the Indian calculating methods to Byzantium in a treatise of 1292.

Theodore Metochites and Nikephoros Gregoras (14th c.), who revived serious Ptolemaic astronomy. Gregoras calculated the date of Easter with precision and proposed a calendar reform in 1324 — two and a half centuries before Gregory XIII adopted a similar correction — which was rejected as likely to cause confusion.

Byzantine astronomers also absorbed Persian and Arabic work: the Persian Syntaxis of George Chrysococces in the 1340s transmitted Ilkhanid astronomical tables into Greek, and these Greek texts were among the material that reached Italy in the fifteenth century.

The Beacon Telegraph

The most impressive Byzantine communications technology was a chain of signal fires running from the Cilician frontier to Constantinople — some nine stations across roughly 700 kilometres of Anatolia, capable of transmitting a warning of an Arab raid in about an hour.

What made it a telegraph rather than a bonfire was the clock. According to the account in later chroniclers, Leo the Mathematician arranged two synchronised water clocks, one at the frontier station and one in the capital, each divided into twelve hours, with each hour assigned a specific meaning: enemy raid, mobilisation, fire, and so on. The beacon was lit at the hour corresponding to the message, so a single fire carried specific information.

The system was reportedly dismantled by Michael III, who is said to have objected to alarms interrupting chariot races in the Hippodrome. The story is told by hostile sources and may be unfair to him; the system itself is well attested.

Mechanics and Automata

The palace held a collection of mechanical devices whose descriptions sound implausible until one remembers that Hellenistic engineers — Ctesibius, Philo, Hero of Alexandria — had built comparable things a thousand years earlier and that their treatises were in the imperial library.

Liudprand of Cremona, received at the Magnaura in 949, described a gilded bronze tree filled with mechanical singing birds, gilded lions that beat the ground with their tails and roared, and a throne that rose toward the ceiling with the emperor on it. He was writing to impress his readers, but the machinery is consistent with Hero’s pneumatics, and the Byzantines were certainly capable of building it.

The devices were destroyed and melted for coin in the tenth century, in one of the empire’s periodic fiscal crises.

Military Technology

Greek fire is the outstanding case: a petroleum-based incendiary projected under pressure through a bronze siphon, which functioned at sea and could not be extinguished with water. It required a pump, a heated pressurised vessel and an ignition system, all built to work on a moving ship — a serious piece of engineering, and one the empire kept secret for centuries.

Byzantine treatises on siegecraft, fortification and tactics form a technical literature with no contemporary equivalent, and the walls of Constantinople are the practical demonstration.

Civil Engineering

The hydraulic system of Constantinople — aqueducts running over 400 kilometres into Thrace, the longest water supply line of the ancient world, feeding open reservoirs and more than a hundred covered cisterns — is described in the Basilica Cistern.

The dome of Hagia Sophia on pendentives, spanning 31 metres over a square plan, was a structural problem no one had solved at that scale before, and the solution shaped a millennium of building in three religions.

Chemistry and the Practical Arts

Byzantine technical manuscripts preserve recipes for pigments, dyes, glass, enamel, gilding, mordants, inks and metallurgy. These are craft texts rather than chemistry, but they represent a substantial body of practical knowledge, transmitted in writing and largely reliable — the manufacture of cloisonné enamel alone required precise control of firing temperatures and material behaviour.

The alchemical tradition also continued: the corpus of Greek alchemical writings, including Zosimos of Panopolis, survives because Byzantine scribes copied it, and it passed to the Arabs from there.

Why Not More?

The absence of a scientific revolution in Byzantium has been explained in several ways: the prestige of ancient authority discouraging challenge; the absence of institutional research; a higher education system aimed at producing rhetoricians and civil servants rather than natural philosophers; and the recurring loss of continuity in periods of crisis.

There is something in all of these. It is also worth noting that the same was true of every other pre-modern society, including the one where the revolution eventually happened, and that Byzantium’s actual achievement — keeping the texts, the teaching and the methods alive for a millennium and handing them on twice, as the transmission of classical learning describes — was the precondition for what followed.

Without Byzantine copies of Euclid, Ptolemy, Archimedes and Aristotle, there is nothing for Baghdad to translate in the ninth century and nothing for Florence to print in the fifteenth.

The Schools

Where science was actually taught is worth establishing, because Byzantium had no universities in the western sense and the institutional history is easily misdescribed.

The Magnaura school, refounded around 855 under the caesar Bardas with Leo the Mathematician at its head, taught philosophy, geometry, astronomy and grammar, with four salaried professors. It is the closest thing to a state institution of higher learning in the middle period.

The patriarchal school, attached to Hagia Sophia, taught rhetoric, exegesis and the enkyklios paideia, and was the principal training ground for the clergy and much of the civil service.

The school refounded by Constantine IX in 1045, with a faculty of law under a nomophylax and a faculty of philosophy under Michael Psellos as hypatos ton philosophon, “consul of the philosophers.”

Private teaching, which carried most of the load throughout. A scholar took pupils for fees, in his own house, and the arrangement was the normal route to an advanced education. Psellos, Italos and their successors taught this way.

The pattern is that institutional provision was intermittent, dependent on imperial interest and funding, and repeatedly interrupted — while private teaching was continuous. That is why the tradition survived the periods when the state had no money for it, and it is a large part of the answer to why Byzantium never developed the corporate universities that western Europe produced from the twelfth century.

The Trial of John Italos

The limits on speculative philosophy had a test case, and it is the best-documented one.

John Italos, a Calabrian Greek, succeeded Psellos as hypatos ton philosophon in the 1070s. He was a genuine Aristotelian and Neoplatonist, more interested in philosophical argument for its own sake than Psellos had been, and less careful about where it led.

In 1082 he was tried before a synod under Alexios I. The charges concerned the eternity of matter, the transmigration of souls, the pre-existence of souls, doubts about the resurrection of the body, and the application of philosophical reasoning to the mysteries of the faith.

He was condemned. The anathemas against him were added to the Synodikon of Orthodoxy, read annually on the Sunday of Orthodoxy, and they include a clause condemning “those who pursue Hellenic studies not merely for education but who follow their vain opinions” — with the crucial qualification that studying the classics for training in reasoning and expression remains permitted.

That qualification is the operative point. The condemnation drew a line: classical philosophy as a tool, yes; classical philosophy as a source of doctrine against revelation, no. Teaching Aristotle continued uninterrupted; Psellos’s own reputation survived; and the schools went on.

It is a real constraint and it was applied once, memorably. Whether it explains the absence of a Byzantine scientific revolution is a much larger claim, and the honest answer is that no pre-modern society had one, including the ones without such constraints.

The Last Byzantine Scientists

The final generation is worth naming, because they carried the tradition across to Italy.

Theodore Metochites (c. 1270–1332), the patron of the Chora, wrote an extensive commentary on Ptolemy’s Almagest and worked to restore mathematical astronomy as a serious pursuit.

Nikephoros Gregoras (c. 1295–1360), his pupil, calculated eclipses accurately, wrote on the astrolabe, and proposed a calendar reform in 1324 — correcting the Julian drift by a method similar to the one Gregory XIII adopted 258 years later. Andronikos II declined it on the grounds that it would cause confusion in the church.

Barlaam of Calabria, better known as Palamas’s opponent, wrote on algebra, astronomy and the calculation of eclipses, and taught Petrarch Greek — badly, by Petrarch’s account.

George Chrysococces translated Persian astronomical tables into Greek in the 1340s, bringing Ilkhanid work into the Byzantine tradition.

Isaac Argyros and Theodore Meliteniotes continued the astronomical work into the later fourteenth century.

Several of these texts went to Italy with the manuscripts described in Bessarion and the Greek scholars, and Bessarion’s commission of Regiomontanus’s Epitome of the Almagest — the book Copernicus used — is a direct line from Byzantine Ptolemaic scholarship to the astronomy that replaced it.

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