Immanuel ben Jacob Bonfils (c. 1300 – 1377) was a

French-Jewish The history of the Jews in France deals with Jews and Jewish communities in France since at least the Early Middle Ages. France was a centre of Jewish learning in the Middle Ages, but persecution increased over time, including multiple expulsio ...

mathematician and astronomer in

medieval In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the Post-classical, post-classical period of World history (field), global history. It began with t ...

times who flourished from 1340 to 1377, a

rabbi A rabbi () is a spiritual leader or religious teacher in Judaism. One becomes a rabbi by being ordained by another rabbi – known as ''semikha'' – following a course of study of Jewish history and texts such as the Talmud. The basic form of ...

who was a pioneer of exponential calculus and is credited with inventing the system of

decimal fractions The decimal numeral system (also called the base-ten positional numeral system and denary or decanary) is the standard system for denoting integer and non-integer numbers. It is the extension to non-integer numbers of the Hindu–Arabic numeral ...

.Vucinich, Alexander (1963). ''Science in Russian Culture, A History to 1860''. Stanford, CA: Stanford University Press He taught astronomy and mathematics in

Orange Orange most often refers to: *Orange (fruit), the fruit of the tree species '' Citrus'' × ''sinensis'' ** Orange blossom, its fragrant flower *Orange (colour), from the color of an orange, occurs between red and yellow in the visible spectrum * ...

and later lived in

Tarascon Tarascon (; ), sometimes referred to as Tarascon-sur-Rhône, is a commune situated at the extreme west of the Bouches-du-Rhône department of France in the Provence-Alpes-Côte d'Azur region. Inhabitants are referred to as Tarasconnais or Tarasc ...

, both towns in the

Holy Roman Empire The Holy Roman Empire was a Polity, political entity in Western Europe, Western, Central Europe, Central, and Southern Europe that developed during the Early Middle Ages and continued until its Dissolution of the Holy Roman Empire, dissolution i ...

that are now part of modern-day

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

. Bonfils studied the works of

Gersonides Levi ben Gershon (1288 – 20 April 1344), better known by his Graecized name as Gersonides, or by his Latinized name Magister Leo Hebraeus, or in Hebrew by the abbreviation of first letters as ''RaLBaG'', was a medieval French Jewish philosoph ...

(Levi ben Gershom), the father of modern trigonometry, and

Al-Battani Abū ʿAbd Allāh Muḥammad ibn Jābir ibn Sinān al-Raqqī al-Ḥarrānī aṣ-Ṣābiʾ al-Battānī ( ar, محمد بن جابر بن سنان البتاني) ( Latinized as Albategnius, Albategni or Albatenius) (c. 858 – 929) was an astron ...

and even taught at the academy founded by Gersonides in Orange. Bonfils preceded any attempt at a European decimal system by 150 years,Blech, Benjamin (2004). ''The Complete Idiot's Guide to Jewish History and Culture''. Indianapolis, IN: Alpha Books publishing the treatise ''Method of Division by Rabbi Immanuel and Other Topics'' ( he, דרך חילוק) on the general theory of

decimal fraction The decimal numeral system (also called the base-ten positional numeral system and denary or decanary) is the standard system for denoting integer and non-integer numbers. It is the extension to non-integer numbers of the Hindu–Arabic numeral ...

s around 1350. This was a forerunner to

Simon Stevin Simon Stevin (; 1548–1620), sometimes called Stevinus, was a Flemish mathematician, scientist and music theorist. He made various contributions in many areas of science and engineering, both theoretical and practical. He also translated vario ...

, the first to widely distribute publications on this topic, and employed decimal notation for integers, fractions, and both positive and negative exponents.Suzuki, Jeff (2009). ''Mathematics in Historical Context''. Washington, DC: The Mathematical Association of America While living in Tarascon in 1365, Bonfils published the work for which he would become best known, ''Sepher Shesh Kenaphayim'' (''Book of Six Wings'') ( he, שש כנפים), a manuscript on

eclipse An eclipse is an astronomical event that occurs when an astronomical object or spacecraft is temporarily obscured, by passing into the shadow of another body or by having another body pass between it and the viewer. This alignment of three ce ...

s that featured astronomical tables predicting future solar and lunar positions (divided into six parts). The book included data for every important date on the

Jewish calendar The Hebrew calendar ( he, הַלּוּחַ הָעִבְרִי, translit=HaLuah HaIvri), also called the Jewish calendar, is a lunisolar calendar used today for Jewish religious observance, and as an official calendar of the state of Israel. I ...

and even correction factors necessary for those who lived as far away as

Constantinople la, Constantinopolis ota, قسطنطينيه , alternate_name = Byzantion (earlier Greek name), Nova Roma ("New Rome"), Miklagard/Miklagarth (Old Norse), Tsargrad ( Slavic), Qustantiniya (Arabic), Basileuousa ("Queen of Cities"), Megalopolis (" ...

. Breaking the tables into six parts was an allusion to the six wings of the

seraphim A seraph (, "burning one"; plural seraphim ) is a type of celestial or heavenly being originating in Ancient Judaism. The term plays a role in subsequent Judaism, Christianity, and Islam. Tradition places seraphim in the highest rank in Chris ...

as mentioned in the

Bible The Bible (from Koine Greek , , 'the books') is a collection of religious texts or scriptures that are held to be sacred in Christianity, Judaism, Samaritanism, and many other religions. The Bible is an anthologya compilation of texts of a ...

Isaiah Isaiah ( or ; he, , ''Yəšaʿyāhū'', "God is Salvation"), also known as Isaias, was the 8th-century BC Israelite prophet after whom the Book of Isaiah is named. Within the text of the Book of Isaiah, Isaiah himself is referred to as "the ...

6:2, earning Bonfils the nickname master of the wings. For 300 years, Bonfils' calculations which were extensively used by sailors and explorers well into the 17th century. The book was translated from

Hebrew Hebrew (; ; ) is a Northwest Semitic language of the Afroasiatic language family. Historically, it is one of the spoken languages of the Israelites and their longest-surviving descendants, the Jews and Samaritans. It was largely preserved ...

into

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

in 1406 by Johannes Lucae e Camerino and into

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

in 1435 by Michael Chrysokokkes. The book inspired Chemist

George Sarton George Alfred Leon Sarton (; 31 August 1884 – 22 March 1956) was a Belgian-born American chemist and historian. He is considered the founder of the discipline of the history of science as an independent field of study. His most influential works ...

to publish his own version of ''Six Wings'' nearly 600 years later. Bonfils translated a number of books from Latin to Hebrew. He also wrote a treatise on the relationship between the diameter and

circumference In geometry, the circumference (from Latin ''circumferens'', meaning "carrying around") is the perimeter of a circle or ellipse. That is, the circumference would be the arc length of the circle, as if it were opened up and straightened out to ...

of a circle and methods of calculating square roots.

Works

* Bonfils, Immanuel (1365), ''The Wings of Eagles'', he, שש כנפים, in six books. Other name: ''Book of Six Wings'', he, שש כנפים. The main astronomical work of Bonfils. * Bonfils, Immanuel (c. 1350), ''The Invention of the Decimal Fractions and the Application of the Exponential Calculus by Immanuel Bonfils of Tarascon''Ragep, F. Jamil and Sally P. Ragep (1996). ''Tradition, Transmission, Transformation''. Netherlands: Brill Academic Pub * Bonfils, Immanuel (c. 1350), ''Method of Division by Rabbi Immanuel and Other Topics'', he, דרך חילוק, a course of decimal arithmetics, including decimal fractions.

References

* Gandz, S.: "The invention of the decimal fractions and the application of the exponential calculus by Immanuel Bonfils of Tarascon (c. 1350)", ''

Isis Isis (; ''Ēse''; ; Meroitic: ''Wos'' 'a''or ''Wusa''; Phoenician: 𐤀𐤎, romanized: ʾs) was a major goddess in ancient Egyptian religion whose worship spread throughout the Greco-Roman world. Isis was first mentioned in the Old Kingd ...

'' 25 (1936), 16–45. * P. Solon: ''The Six Wings of J. Bonfils and Michael Chrysokokkes'', in: Centaurus, 15 (1970) 1–20

External links

BONFILS, IMMANUEL BEN JACOB
in Jewish Encyclopedia.
Six Wings.
{{DEFAULTSORT:Bonfils, Immanuel 1300 births 1377 deaths Jewish astronomers 14th-century mathematicians Medieval French mathematicians 14th-century astronomers Medieval Jewish astronomers Medieval French astronomers 14th-century French writers Jewish writers 14th-century translators 14th-century Latin writers