Qusta ibn Luqa

Qusta ibn Luqa (Latin: Costa ben Luca) was a Melkite Christian scholar — that is, a member of the Greek-rite Christian community of the Near East — who became one of the leading figures of the great ninth-century movement that translated Greek learning into Arabic. He was a physician, astronomer, mathematician, and natural philosopher as well as a translator. Sources describe him as fluent in Greek, Syriac, and Arabic.

He was born, probably around 820 CE, in Baalbek (ancient Heliopolis, in present-day Lebanon). His working life centred on Baghdad, the Abbasid capital, where he served a range of patrons — members of the caliphal family, senior officials, and a Christian patriarch. He is reported to have collected Greek scientific manuscripts on journeys into Byzantine territory and then translated or revised them. The bibliographer Ibn al-Nadim (died c. 990) praised him as an excellent translator who "corrected many translations," and rated his medical standing highly.

His output, traditionally said to exceed sixty treatises, ranged across medicine, astronomy (including a widely copied work on the celestial globe), mathematics, and philosophy. A short treatise distinguishing "spirit" from "soul" circulated in Latin in medieval Europe.

He died, probably around 912–913 CE, in Armenia, where tradition holds he was an honoured guest of a local ruler named Sanharib. His birth and death dates are traditional estimates rather than securely documented, and should be read as approximate.