Four Englishmen—Adelhard of Bath (c. 1130), Robert of Chester (Robertus Cestrensis, c. 1143), William Shelley, and Daniel Morley (1180)—are known[[506]] to have journeyed to Spain in the twelfth century for the purpose of studying mathematics and Arabic. Adelhard of Bath made translations from Arabic into Latin of Al-Khowārazmī's astronomical tables[[507]] and of Euclid's Elements,[[508]] while Robert of Chester is known as the translator of Al-Khowārazmī's algebra.[[509]] There is no reason to doubt that all of these men, and others, were familiar with the numerals which the Arabs were using.
The earliest trace we have of computation with Hindu numerals in Germany is in an Algorismus of 1143, now in the Hofbibliothek in Vienna.[[510]] It is bound in with a
Computus by the same author and bearing the date given. It contains chapters "De additione," "De diminutione," "De mediatione," "De divisione," and part of a chapter on multiplication. The numerals are in the usual medieval forms except the 2 which, as will be seen from the illustration,[[511]] is somewhat different, and the 3, which takes the peculiar shape
It was about the same time that the Sefer ha-Mispar,[[512]] the Book of Number, appeared in the Hebrew language. The author, Rabbi Abraham ibn Meïr ibn Ezra,[[513]] was born in Toledo (c. 1092). In 1139 he went to Egypt, Palestine, and the Orient, spending also some years in Italy. Later he lived in southern France and in England. He died in 1167. The probability is that he acquired his knowledge of the Hindu arithmetic[[514]] in his native town of Toledo, but it is also likely that the knowledge of other systems which he acquired on travels increased his appreciation of this one. We have mentioned the fact that he used the first letters of the Hebrew alphabet,
א ב ג ד ה ו ז ח ט
, for the numerals 9 8 7 6 5 4 3 2 1, and a circle for the zero. The quotation in the note given below shows that he knew of the Hindu origin; but in his manuscript, although he set down the Hindu forms, he used the above nine Hebrew letters with place value for all computations.