John of Seville

Who is John of Seville?

John of Seville was the main translator from Arabic into Castilian together with Dominicus Gundissalinus during the early days of the Toledo School of Translators. His work is said to have flourished between 1135 and 1153.

He was a baptized Jew, whose Jewish name has been corrupted into "Avendeut", "Avendehut", "Avendar" or "Aven Daud". This evolved into the middle name "David", so that, as a native of Toledo, he is frequently referred to as Johannes Toletanus. Some historians argue that in fact there were two different persons with a similar name, one as Juan Hispano and other as Juan Hispalense, this last one perhaps working at Galician Limia, for he signed himself as "Johannes Hispalensis atque Limiensis", during the Reconquista, the Christian campaign to regain the Iberian Peninsula.

The topics of his translated works were mainly astrological and astronomical, philosophical and medical. At least three of his translations, the Secretum Secretorum dedicated to a Queen T[arasia?], a tract on gout offered to one of the Popes Gregory, and the original version of the 9th century Arabic philosopher Costa ben Luca's De differentia spiritus et animae, were medical translations intermixed with alchemy in the Hispano-Arabic tradition. In his Book of Algorithms on Practical Arithmetic, John of Seville provides one the earliest known descriptions of Indian positional notation, whose introduction to Europe is usually associated with the book Liber Abaci by Fibonacci: