During the eleven centuries of the Byzantine Empire (330-1453), Byzantine scholars have been deeply concerned with the preservation of the scientific and cultural legacy from Antiquity. Aware indeed that they are the heirs of the great scientists such as Euclid, Archimedes or Ptolemy, they never abandoned the study of their works, editing and commenting the Ancient treatises, or writing new works to continue the Hellenic tradition. On the other hand the permanent contacts which they had with their Oriental neighbours, although often conflictual, put them in touch with important works written in Arabic or Persian: some of these works were translated and adapted in Greek, and became very influential in astronomy or medicine. Later, a Latin influence can be noticed and at the very end of the Byzantine Empire, in the fifteenth century, Jewish treatises also emerged to a remarkable extent among Byzantine scientists.

The end of Antiquity (Fourth-Seventh Centuries)

In the early Eastern Roman Empire, intellectual formation was assumed by renowned schools such as Athens, Antioch, Beirut, Apameia, Rhodos, Alexandria ... Alexandria was at that time the most important center for scientific teaching and medical formation. The scientific teaching of the Alexandrian schools consisted mainly in studying and commenting the ancient scientific treatises (Euclid, Archimedes, Ptolemy, Apollonius and many others). Constantinople also developed advanced teaching in the imperial school, which was reorganized in 425 by Emperor Theodosius II. The programme taught in Constantinople was planned mainly for the formation of civil servants, in order to make them competent in Greek and Latin languages. The activity of the Ancient schools continued until the sixth century in spite of difficult political circumstances, such as the religious riots in Alexandria which caused the death of the famous philosopher Hypatia, murdered in 415 by the Alexandrian mob.

The Christianisation of the Roman Empire had little effect on scientific studies, except in the Nestorian schools of Edessa and Nisibis, where a Christian cosmology was elaborated in conformity with the Holy Scriptures. This cosmology was promoted in Alexandria by Cosmas Indicopleustes (ca 534-547) in a book entitled Christian Topography: the heavens have the form of a vaulted chest, like Moses’ Tabernacle and the earth is a flat rectangle. Such views were criticized by John Philoponus who defended the Aristotelician conception of a spherical Universe. Cosmas’ cosmology reappeared in Constantinople in the twelfth century.

Justinan’s reign (527-565) saw a major achievement: the construction of Haghia Sophia, an architectural masterpiece due to the engineers and geometers Anthemius of Tralles and Isidorus of Miletus. But the ancient schools gradually declined. In 529 Justinian ordered the closure of the school of Athens, which promoted an aggressive paganism. The teachers took refuge for a time at the court of the Persian King Chosroes I (531-579); Antioch was partly destroyed by an earthquake in 526; Beirut fell into ruin after an earthquake in 551. Alexandria resisted longer, but the city was taken first by the Persians, and finally by the Arabs in 641. The capture of Alexandria marks the end of the schools of the Antiquity. The transmission of scientific knowledge was closely linked to the survival of the Hellenic education in the Eastern Roman Empire. When these schools disappeared, scientific education was threatened with vanishing entirely. But during the difficult years of the fifth and sixth centuries, the scientific legacy was partly transmitted through the Oriental world, in Persia, Armenia and Syria, and mainly to Constantinople which became and will remain the most important intellectual centre of the Empire.

1- The son of Menofron, astronomer Theodosius’ grave stone. The scientist who lay down over a marble bed touching a sphere with a stick in his hand. The sundial on the left upper corner of the gravestone implies that the scholar was interested in astronomy (2nd century BCE) (Istanbul Archeology Museum)

Seventh and Eight Centuries

At the beginning of the seventh century Constantinople had lost the major part of its Oriental provinces and also Egypt as a result of the Arabic conquest. The Imperial school took over the scientific teaching previously assumed by Alexandria. Under the Emperor Heraclius (610-641), an astronomical commentary was written around 617 presumably by Stephanus of Alexandria, one of the last philosophers of the Alexandrian tradition. The level of this commentary is elementary, in imitation of the Small Commentary of Theon of Alexandria (ca 364 AD), but Ptolemy’s Handy Tables were adapted for Constantinople: this appears to be the first Byzantine astronomical manual, which marks the transition between Alexandria and Constantinople.

The seventh century is a dark period, disturbed by the war of Heraclius against Persia, the Arab conquest and the political troubles after the death of Heraclius. An important military discovery was “Greek fire”, a mixture of resin and sulphur, or oil from the Sea of Azov, which was propelled by a pump and a bronze tube against the boats of the enemies. The invention was improved by a Syrian named Callinicus in the seventh century and it saved Constantinople from the Arabs in 678. It ensured the superiority of the Byzantine navy over centuries, but the secret of its fabrication has been extremely well preserved!

The iconoclast crisis of the eighth century was also very damaging for the development of scientific teaching. All that we know about this period is that education still included a study of the “four sciences” (quadrivium, i.e. arithmetic, geometry, astronomy, music), a programme inherited from Antiquity which seems to have been followed at a basic level in secondary schools. John of Damascus, the great defender of the Images, in his work De fide orthodoxa, gives a short account of the scientific knowledge appropriate for a Christian, in which he hesitates about the shape of the Earth (spheric, flat or conic ...).

Ninth and Tenth Centuries

One must wait until the ninth century in order to see a remarkable revival, a movement which Paul Lemerle called the “First Byzantine Humanism”. In Western Europe as well as in the Arabic world and the Byzantine Empire, culture emerged from the deep stagnation in which it was immersed for two centuries. The Golden Age of Arabic science starts at that time, but the progress of the Arabs in astronomy and mathematics would not be known immediately in the Byzantine world. In Constantinople, an extensive movement was launched thanks to the Patriarch Photius for the restoration of the Libraries. Many beautiful manuscripts were copied in scriptoria, such as the Scriptorium of the Monastery of Stoudios in a new elegant handwriting, the minuscule, more readable than the ancient uncial script. Among the most ancient manuscripts which were copied at that time can be mentioned the works of Euclid, Ptolemy and Theon of Alexandria. The movement of transcribing ancient manuscripts on a large scale saved hundreds of works from oblivion and destruction.

Nevertheless, in spite of several reforms of the Imperial School, the ninth century did not leave us an important scientific legacy. The most famous scientist of the time, Leon the Mathematician, whose life prompted many legendary accounts, did not leave any important works, except a high reputation as an astrologer and an optical telegraph which could send regular signals from the border of the Empire (North of Tarsus) to Constantinople. At that time, one observes a certain taste of mechanical devices. The Emperor Theophilus (829-842) owned a collection of automata. The Imperial Throne of Constantinople had mechanisms which could lift the throne up to the ceiling while bronze lions were roaring and swishing their tails, griffons stood up and birds started to sing in golden trees. Such devices were built according to the ancient techniques described by Philo (second century) or Heron of Alexandria (first century AD), an author whose works were transmitted in a splendid Constantinopolitan manuscript copied in the tenth century.

The tenth century is a period of encyclopedism. An erudite Emperor, Constantin VII Porphyrogenitus (913-959) had planned to compile a vast collection of all knowledge available in his time. Under his influence were compiled many collections of works, for example the Geoponica, an encyclopedia devoted to agriculture (vineyard, olive, fruits, vegetables, trees ...). Based on ancient sources collected first by Vindianus Anatolius of Berytus in the fourth century AD, and afterwards by Cassianus Bassus in the sixth century, this work became very popular and was translated into Latin, Arabic, Syriac and Armenian. A collection of ancient alchemists was copied in a tenth century manuscript, the Marcianus gr. 299, illustrated by drawing of the instruments used by alchemists. In the same way, many medical works were compiled in manuscripts of the tenth century, as well as hippiatric or zoological works. Collection of ancient geographers were copied in manuscripts of the ninth –tenth centuries.

Ninth and Twelfth Centuries

In the eleventh century, Arabic influence appeared for the first time in Byzantine scientific texts, especially in astronomy. From the beginning of the tenth century the Arabs had initiated new astronomical researches in the observatories built in Bagdad and Damascus under the caliph al-Ma‘mūn (813-833). A notice of these researches can be found in astronomical scholia written towards 1032, and copied by a later hand in a manuscript of Ptolemy (Vaticanus gr. 1594). The author quotes the works of more recent astronomers and observations made in 829/830 in Baghdad and Damascus. But having no access to these works, as he says, he will use the work of another astronomer called Alim (Ibn al-A‘lam, d. 985). This text shows that Alim’s tables have been adapted for Constantinople in the years 1032 ss. Other documents confirm the presence in Constantinople of several scientists, perhaps of oriental origin, able to read and to use Arabic mathematical and astronomical works. A treatise of ca. 1072 (Parisinus gr. 2425) makes use of a commentary of Ibn al-Muthannā on al-Khwārizmī concerning solar eclipse calculation and of the tables of sine and versed sinus of Habash al-Hāsīb. An astrological compilation in the Vaticanus gr. 1056 contains a treatise on the astrolabe “from a Saracen book” and star lists dated from 1155/6 and 1160/1 from oriental sources. The only preserved Byzantine astrolabe, the Brescia astrolabe, was crafted in 1062 for a certain Sergius, a man of Persian origin. Simeon Seth, a physician and astrologer of Alexios I Komnenos (1081-1118), also translator in Greek of the Arabic fables Kalila wa Dimna (in Greek Stephanites and Ichnelates) knew the Arabic value of precession.

The Greek tradition is also represented by an anonymous quadrivium dated from 1007-1008.

Natural sciences were also cultivated in Byzantium but their range was less clearly defined than the sciences of the quadrivium. One can find for example encyclopedic writings in the eleventh century (Michael Psellos, Simeon Seth) in which natural phenomena (winds, earthquakes, comets, geography, etc.) are explained in a superficial way on bases of Aristotle or Plutarch. Micheal Psellos, the great polymath of the time introduced a new kind of teaching, proceeding by “questions and answers”. He was interested also in alchemy, and esoteric matters.

Zoology seems to have excited the greatest interest in the tenth to twelfth centuries. The Emperor Constantine IX Monomachos (1042-1055) had established a zoo in Constantinople, and Michael Attaliates (eleventh) described an elephant and a giraffe which were displayed there. In the learned circle of the Princess Anna Comnena (twelfth), Michael of Ephesus commented the zoological writings of Aristotle.

Thirteenth–Fifteenth Centuries

In 1204 Constantinople was captured by the Latin’s during the Fourth Crusade. This was accompanied by pillages and much destruction. During Latin rule, Byzantine scholars gathered at the court of Nicaea tried to restore advanced teaching. In 1261, the Emperor Michael Palaeologos recaptured Constantinople and it was the beginning of most prolific period of the Byzantine intellectual life. In order to repair damages caused by the Latin occupation, many scientific manuscripts were recopied and restored, a task which was made easier by the plentiful introduction of paper, a material less expensive than parchment. Texts are not only copied, but carefully edited and corrected. Many new commentaries are composed, especially in the four traditional disciplines: arithmetic, geometry, astronomy and music.

Arithmetic is divided between two branches: learned and practical arithmetic.

2- An astronomer’s gravestone with a sundial (2<sup>nd</sup> century BCE) (Istanbul Archeology Museum)

Learned arithmetic was based on ancient sources: Euclid, Archimedes, Nicomachus of Gerasa (IId c. AD), Theon of Smyrna (IId c. AD), Diophantus (ca 250 AD), Heron (first c. AD), Pappus (ca 323), Theon of Alexandria (ca 364), and others. Explanations of the sexagesimal system are considered as an introduction to astronomy, the reason why they are mainly found in astronomical treatises. The following works contain important arithmetical sections: the Quadrivium of George Pachymeres (ca 1300), the Stoicheiôsis of Theodore Metochites (ca 1300), Book I of the Astronomical Tribiblos of Theodore Meliteniotes (ca 1352), and many anonymous compilations. The extraction of square roots attracted the attention of Isaac Argyrus (ca 1368) who devoted a short tract to it. The Logistic of Barlaam (ca 1337) is an account of arithmetical theorems based on Euclid. The Introduction on the Almagest written by George of Trebizond shortly after the Conquest of Constantinople (ca 1461) is a compromise between traditional Greek methods and new procedures imported from the Western world. It contains virulent attacks against Theon and Geber (Jābir ibn Aflah, twelfth c.) and introduces a new terminology for the terms of a ratio. This work was dedicated to the Sultan Mehmed II whom George wanted to meet in Istanbul in order to offer him his services, but he could never get an audience and his travel was a failure.

Practical arithmetic was based first on digital calculation, that is by the fingers of the hand. A striking description is given by Nicholas Mesarites (ca 1200) of a class in the school attached to the Holy Apostles Church in Constantinople: terrified children learn reckoning on their fingers, while the blows of the rope or of the whip rain over them at the least error. Digital calculation is described by Nicholas Rhabdas (ca 1341). The procedures of Indian calculation, with Indian numerals in the Western form are explained in an anonymous treatise composed in 1252, at the time of Latin rule (Indian Calculation, called the Great calculation). The subject was treated again by Maximus Planudes (ca 1293) who uses the oriental shape of the Indian numerals. Indian calculation does not seem to have had a real success at least in scholarly circles. Around 1300, Manuel Moschopoulos wrote a tract on magical squares. Several anonymous treatises from the fourteenth and fifteenth centuries written in vernacular Greek are collections of problems involving coins, measures, and inheritance, solved by algebric procedures.

Astronomy is also divided in two tendencies: the Ptolemaic tradition and the foreign influence.

The Greek tradition appears in the Quadrivium of George Pachymeres, but the astronomical part of this work deals mainly with sexagesimal calculation and constellations. It is mainly Theodore Metochites who promoted the astronomy of Ptolemy in his Stoicheiosis. His pupil Nicephorus Gregoras went a step further in predicting solar eclipses (1330, 1333, 1337) according to the Ptolemaic procedures. Gregoras’ rival, the monk Barlaam of Seminara (Calabria) also published two eclipse calculations according to the Almagest (Solar eclipses of 1333 and 1337). Ptolemy’s methods are also explained in details in Book II of the Astronomical Tribiblos of Theodore Meliteniotes (ca 1352). Later, Isaac Argyros adapted for the Byzantine world the tables of Ptolemy for syzygies, Sun and Moon (New Tables). Ptolemy’s methods were used until the very end of the Byzantine Empire, especially for eclipse calculations. During the fourteenth and fifteenth centuries, the main work of Ptolemy, the Mathematike Syntaxis (Almagest) was intensively studied by Byzantine scholars, who left many annotations or comments in the margins of the Almagest.

3- An effigy found in Gedikpaşa excavations, which is assumed to belong to a philosopher (Istanbul Archeology Museum)

The foreign influence came first from Persia. At the end of the thirteenth century, the Mongols invaded the entire Oriental world to the borders of the Byzantine Empire. Il-Khan Hulagu, the grandson of Genghis Khan, built the famous observatory of Maragha, not far from Tabriz, at the doors of Trebizond. Under the direction of Nasīr ad-Dīn at-Tūsī (ca 1270), the reputation of Persian astronomy spread everywhere and the observatory attracted many foreign students. Thanks to the travels of George (Gregory) Chioniades, future Bishop of Tabriz, and probably of other travellers, Persian astronomy was translated into Greek. Chioniades brought many books of astronomy to Trebizond and translated them into Greek. His books were left to a priest named Manuel. Several manuscripts dated from the end of the thirteenth century and from the fourteenth century contain translations of Persian astronomical treatises, especially the teaching of Shams Bukhari. These translations are probably the work of Chioniades and other collaborators. But these translations were especially difficult for a Byzantine reader, for many technical words are not translated, but simply transcribed in Greek letters. Manuel of Trebizond is probably the author of astrological ephemerides compiled for Trebizond in 1336. He had among his pupils a man called George Chrysococces, who wrote a Persian Syntaxis around 1347. This work is a Greek adaptation of the Zîj i-Ilkhani of Nasīr ad-Dīn at-Tūsī (ca 1270). The Persian Syntaxis is written in a good Greek, understandable to everybody, and the methods are illustrated by examples. As a result, this work met with an enormous success and gained a wide diffusion in Constantinople, Cyprus, Rhodes, Mitylene, and elsewhere. It was translated into Hebrew by a Jewish scholar of Thessaloniki (Shlomo ben Eliahu ca 1374-1386), and into Latin in Crete. Persian astronomy was also adapted by Theodore Meliteniotes in Book III of his Astronomical Tribiblos (ca 1352). In his Persian Syntaxis, Chrysococces had insisted on the astrological aims of astronomy, especially for practising astrological medicine (iatromathematic). In contrast, Meliteniotes condemns astrology very severely and defends the study of astronomy as a glorification of God’s creation. Theodore Meliteniotes was the director of the Patriarchal School, and his work demonstrated the importance of astronomy for the intellectual training of the members of the Orthodox Church.

At the end of the fourteenth century and in the fifteenth, other influences appear, as in a Byzantine adaptation of the Alphonsine Tables by Demetrius Chrysoloras (ca 1380). Latin astronomy was already known in Cyprus (under the rule of the Lusignan), but Latin astronomy will be less influential, except for some treatises on the astrolabe.

At the beginning of the fifteenth century, Byzantine scholars discover the Jewish astronomical tables. Three Jewish astronomical works were the object of Byzantine adaptation: the Six Wings (Shesh Kenaphayim , in Greek Hexapterygon) of Emmanuel Bonfils of Tarascon (ca 1365), adapted by Michael Chrysococces (ca 1434-5); the Cycles of Bonjorn (Jacob ben David Yom-Tob, Perpignan, ca 1361), adapted by Mark Eugenicus (ca 1434 ?); the Paved Way (Orah Selulah) of Isaac ben Salomon ben Zaddiq Alhadib (ca 1370-1426) adapted by Matthew Camariotes (d. 1490-1) These treatises will continue to be studied during the Ottoman period.

A Jewish influence can be discovered in the background in the astronomical treatise of George Gemistus Plethon. This manual is the only astronomical work entirely original in the Byzantine world. Plethon’s astronomy is based on his ideas for the restoration of pagan antiquity, including a new calendar imitating that of the ancient Greeks and Romans. The tables are established for the longitude of Mystra in the Peloponnese, beginning 1433 Dec 13, a date when the New Moon falls at the Winter Solstice the sources used by Plethon include a Hebrew version of al-Battānī.

The astronomical studies in Byzantium also include two special types of works: the treatises on the astrolabe, and Easter computation.

The plane astrolabe was described in many treatises following the Greek tradition first represented in Alexandria by John Philoponus (ca 520-550) and later by Nicephorus Gregoras (ca 1330), Theodore Meliteniotes (ca 1352), Isaac Argyros (ca 1370); the Latin tradition appears in a translation of the Pseudo-Messahalla (1309) and anonymous treatises written in Constantinople (thirteenth c. ?) and Cyprus (ca 1340); the Oriental tradition is represented by the treatise of Siamps the Persian (XIVth c.). As we have seen, only one Byzantine astrolabe has been preserved, the Brescia astrolabe crafted in 1062 for Sergios the Persian. Other instruments probably did exist, but there is only one anonymous treatise on the armillary astrolabe and also a work on the quadrant, adapted from Latin sources.

Easter computation involved two astronomical problems: the date of the Spring equinox and the date of the Full Moon following the equinox. The question had been solved by the Council of Nicaea in 325, but the subject still raised problems especially in the seventh century as shown by several computi written at that time (Maximus the Confessor, Heraclius, George the Monk and Priest). The question arose again in the fourteenth century with the account of Nicephorus Gregoras and the treatise of Barlaam. Both were developing the astronomical problems (length of the solar year, lunar cycles...) but based only on Ptolemy’s parameters, even if Gregoras adds a remark saying that Ptolemy’s value of the solar year is not exact. Gregoras suggests a reform of the Pascal rules, but it does not seem to have been accepted by the Emperor Andronicus II. Nicholas Rhabdas and Isaac Argyros also wrote on the subject.

Annexe: Chronological Survey


Reorganization of the public teaching by Teodosius II


Copy of the Vienna Dioscorides illustrated


Justinian forbids Pagan teaching, closure of the neoplatonician school of Athens

ca 537

Anthemius of Tralles, mechanician, architect
(Haghia Sophia); treatises on Burning mirrors, on Remarkable Mechanisms

ca 537

Isidorus of Miletus, geometer, architect (Haghia Sophia)


Inauguration of Haghia Sophia


Christian Topography of Cosmas Indicopleustes

ca 617

Astronomical commentary of Stephanus


Capture of Alexandria by the Arabs

ca 670

Invention of the “Greek Fire” by a Syrian Callinicus

eighth century

Iconoclast crisis

ca 754

John of Damas, theologian, De fide orthodoxa

ninth century

“First Byzantine Humanism”, transliteration of many manuscripts

ca 840

Leon the Mathematician (astrology, optic telegraph)

tenth century

Constantine VII Porphyrogenitus (913-959), encyclopedic compilations in agriculture, medicine, hippiatry, botany, alchemy, geography ...

eleventh century

Arabic influence on Byzantine astronomy


Anonymous quadrivium based on classical sources

ca 1018-1081

Michael Psellos, historian, philosopher, polymath; encyclopedic writings, alchemy

1032 ss

Tables of Alim


Astrolabe of Brescia


Arabo-Byzantine manual of astronomy

ca 1080ss

Symeon Seth, translator of the Arabic tales Kalila wa Dimna (Stephanites and Ichnelates), astrologer, physician,

twelfth century

Michael of Ephesus, zoology


Nicolas Mesarites, description of the school of the Holy Apostles in Constantinople


Capture of Constantinople by the Fourth Crusade. Byzantine scholars at the Court of Nicaea


Anonymous treatise of Indian Calculation


Michael Palaeologus recaptures Constantinople; beginning of the “Byzantine Renaissance”

ca 1270

Foundation of the observatory of Maragha
(near Tabriz) by the Mongols

ca 1290-1300

George (Gregory) Chioniades travels in Persia; translations of Persian and Arabic treatises

ca 1293ss

Maximus Planudes, Indian Calculation, study of Diophantus, of Ptolemy’s Geography

1300 ?

Byzantine adaptation of Siamps the Persian
(astrolabe treatise)

ca 1300

George Pachymeres, Quadrivium
(arithmetic, astronomy, geometry, music)

ca 1300

Manuel Moschopoulos, Magic Squares

ca 1300

Theodore Metochites, Stoicheiosis
(Elements of Astronomy)

ca 1300

Manuel Bryennius, Harmonics


Byzantine translation of the Pseudo-Messahalla (astrolabe)

ca 1320

Manuel Philes, poem on zoology


Nicephorus Gregoras, eclipses calculations, astrolabe, harmonic, Easter comput

ca 1332ss

Barlaam of Calabria (Seminara): Logistic, Solar eclipses of 1333 and 1337, Easter comput, harmonic


Trebizond ephemerides (by Manuel of Trebizond ?)

ca 1340

Western astronomy adapted in Cyprus (astrolabe, Toledan tables)

ca 1341

Nicholas Rhabdas, arithmetical treatises, Easter computi

ca 1347

George Chrysococces, Persian Syntaxis

ca 1350

Neophytos Prodromenos, Botanical lexicon

ca 1352

Theodore Meliteniotes, Astronomical Tribiblos (I, astrolabe, arithmetic; II, Ptolemy’s astronomy; III, Persian tables).

ca 1368

Isaac Argyros, New Tables (astronomy), Square root, Easter computus, astrolabe

ca 1380

Demetrius Chrysoloras, adaptation of the Alphonsine tables

ca 1433

Demetrius Pepagomenus, treatises on hunting dogs, falconry


George Gemistus Plethon, philosopher, supporter of a neo-paganism, astronomical tables for Mystra

ca 1434

Michael Chrysococces, adaptation of the Six Wings of Immanuel Bonfils

ca 1434

Marc Eugenicus, adaptation of the Cycles of Bonjorn


Conquest of Constantinople, taken by Mehmed II

ca 1460 ?

Matthew Camariotes, adaptation of the Paved Way of Alhadib


George of Trebizond, Introduction to the Almagest (arithmetic) dedicated to the Sultan Mehmet II.

One cannot speak of astronomy without mentioning astrology. Astrology was always practised in Constantinople in spite of the recurrent condemnations by the Church. The Byzantines, at least educated people, did not confuse astronomy (theory) and astrology (practice). There are many Byzantine astrological manuscripts, based on ancient authors (Ptolemy, Vettius Valens, Paul of Alexandria, Hephaestion, etc.) or modern (Abu Ma’shar, etc.). Generally speaking, many Byzantine scholars claimed that they did not believe in astrology, at least for individual predictions, but they accepted the idea that celestial phenomena such as eclipses might be announcements of physical or political events.

Geometry was not developed in many new Byzantine treatises except the anonymous quadrivium of 1007/1008 and the quadrivium of George Pachymeres, both based on Euclid. The study of geometry was made directly through the text of Euclid, whose works never ceased to be studied by the Byzantines. There are also some tracts on geodesy in which practical procedures are explained for ground measurement, but the procedures are far from exact.

In the ancient tradition, music was based on the tetrachord (a lyre with four chords), the pitch of the note being changed by the tension of the chord. A tetrachord had two fixed notes (the external chords) and two moving notes (the two inside chords). Several tetrachords were joined together in order to create one larger musical scale. According to the tension of the chords one could obtain various successions of intervals which created the musical scales: diatonic (½ tone + 1 tone + 1 tone), chromatic (½ tone + ½ tone + 1 ½ tone) or enharmonic (¼ tone + ¼ tone + 2 tones). An important part of musical theory consisted in studying the mathematical ratios representing the musical intervals. The ancient musical theory is explained as expected in the anonymous quadrivium of the XIth century and in the quadrivium of George Pachymeres. At the beginning of the XIVth century many Byzantine scholars were interested by musical theory: Manuel Bryennios compiled a large treatise on basis of ancient authors; Nicephorus Gregoras and Barlaam also wrote on the subject.

Geographywas partly linked to astronomy, since the astronomical tables included long lists of “famous cities” with coordinates in longitude and latitude. Ptolemy’s Geography was studied around 1300 by Maximus Planoudes and Strabon was often studied in the fourteenth and fifteenth centuries.

Botany aroused much interest: for, in Antiquity plants were interesting above all for their medicinal properties, and for their magical power. The Materia Medica of Dioscorides (first century AD), which constituted the basis of Byzantine botany, was transmitted to us in a famous manuscript preserved in Vienna, copied in 512 by order of Julia Anicia, and superbly illustrated. The magnificent drawings of plants in the Vienna Dioscorides are the source of many illustrated Byzantine botanical manuscripts. The botanical lexicon or glossary is the most usual form through which botany was transmitted in Byzantium. Most of the lexica are anonymous, except the lexicon of Neophytos Prodromenos. The monk Neophytos Prodromenus (ca 1350s) compiled this lexicon probably for the needs of the hospital founded by the Serbian King Uros II Milutin in the monastery of the Prodromos, at Petra in Constantinople. Certain late glossaries give, alongside the Greek names of plants, their Latin, Arabic, Italian or Turkish names.

Many magical or hermetic texts concern plants, as for example the Kyranides, a collection of magical recipes of the third or fourth centuries. In hermetic writings, plants are associated by sympathy or antipathy to the animal or mineral kingdom, or to zodiacal signs, and other astrological elements. Anonymous texts mix together pharmaceutical recipes and magical practices.

In the fourteenth around 1320, Manuel Philes (1275-1345) wrote a poem on the characteristics of animals, based on Elian. Later Demetrius Pepagomenus, in the fifteenth, wrote treatises on hunting dogs and falconry.

Alchemy is represented by a compilation of ancient alchemists already mentioned above in the Marcianus gr. 299 (tenth c.); it reappears in some writing of Michael Psellos and Nicephorus Blemmydes, but also in late anonymous writings which give collections of recipes of Latino-Arab origin.


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This article was translated from Turkish version of History of Istanbul with some editions to be published in a digitalized form in 2019.