Isaac ben Moses Eli ha-Sefaradi was a fifteenth century Spanish

Jewish Jews ( he, יְהוּדִים, , ) or Jewish people are an ethnoreligious group and nation originating from the Israelites Israelite origins and kingdom: "The first act in the long drama of Jewish history is the age of the Israelites""The ...

mathematician, born at Oriola,

Aragon Aragon ( , ; Spanish and an, Aragón ; ca, Aragó ) is an autonomous community in Spain, coextensive with the medieval Kingdom of Aragon. In northeastern Spain, the Aragonese autonomous community comprises three provinces (from north to sou ...

. According to Steinschneider, he may have been one of the Spanish exiles of 1492, probably leaving to

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 (" ...

. He wrote a mathematical work entitled ''Meleket ha-Mispar'', divided into three parts: (1) a theory of numbers, dealing with the first four rules and the extraction of square roots; (2) proportion, etc.; and (3) elementary geometry. The book is an introduction to

Euclid Euclid (; grc-gre, Wikt:Εὐκλείδης, Εὐκλείδης; BC) was an ancient Greek mathematician active as a geometer and logician. Considered the "father of geometry", he is chiefly known for the ''Euclid's Elements, Elements'' trea ...

, and begins with a definition of the science of figures.

References

* Steinschneider, ''Bibliotheca Mathematica'', 1901, p. 74. * Steinschneider, ''Jewish Literature'', p. 192. * 15th-century Spanish mathematicians 15th-century Aragonese Jews {{mathematician-stub