Abraham ibn Ezra

Abraham ben Meir ibn Ezra, known to English readers as Rabbi Ben Ezra, was a Jewish scholar who was born in Tudela in 1092 and died in 1167 in Calahorra, and who lived in Muslim Spain before a long period of wandering. He made his name as a scholar and a poet, travelled in North Africa, and from about 1140 was forced to move through Europe, settling for a time in Rome and then Lucca, where he wrote his most famous works. He wrote on grammar, exegesis, philosophy, medicine, astronomy, astrology, the calendar, the astrolabe, and permutations and combinations. For the history of mathematics his most important writings are three treatises on numbers, including the Book of the Unit on the Indian symbols for the digits and the Book of the Number on the decimal place-value system, in which he uses zero under the name galgal. These helped bring Indian numerals and decimal fractions to the attention of learned readers in Europe, centuries before they were widely accepted, and he spread the learning of the Arabs at a time when scholarship in Christian Europe had been neglected.