They began again to apply themselves to commerce, of which they were the masters: they traded with the south of Europe, and thus accumulated vast sums, which they transferred from one hand to another by means of bills of exchange――an invention for which commerce is said to be indebted to them, and which enabled them to transfer their wealth from land to land, that when threatened with oppression in one country, their treasure might be secured in another. The learned amongst them employed themselves in literature and science, and promoted the same amongst their Christian neighbours. Whilst the Christians of that period were groping in the darkness of superstition and ignorance, the Jews enjoyed and improved the sunshine of intellect and knowledge. They were honoured in Spain by the appellation of _sapientissimi_. Whilst the Greek authors were totally neglected by Christians――and even John of Salisbury, though a few Greek words are to be found in his compositions, seems to have had only the slightest possible acquaintance with that language――the Jews, however, were reading, in their own language, several works of Aristotle, Plato, Ptolemy, Apollonius, Hippocrates, Galen, and Euclid, which they derived from the Arabic of the Moors, who brought them from Greece and Egypt, and employed much of their time in writing dissertations and controversial arguments upon them. They were the means, therefore, of the old classics being actively disseminated amongst the western colleges of Christendom. The Jews also held the principal chairs of mathematics in the Mahommedan colleges of Cordova and Seville; they came in contact with many Christians, and spread themselves into various countries; they taught the geometry, the algebra, the logic, and the chemistry of Spain, in the universities of Oxford and Paris, while Christian students from all parts of Europe repaired to Andalusia for such instruction.¹ ¹ See “the Fundamental Principles of Modern Judaism Investigated,” pp. 238, 239. Also “An Apology for the Study of Hebrew and Rabbinical Literature,” by the Rev. Dr. M‘Caul. In this country, the Jews had schools in London, York, Lincoln, Lynn, Norwich, Oxford, Cambridge, and other towns, which appear to have been attended by Christians as well as by those of their own persuasion. Some of these seminaries, indeed, were rather colleges than schools. Besides the Hebrew and Arabic languages, arithmetic and medicine are mentioned among the branches of knowledge that were taught in them; and the masters were generally the most distinguished of the rabbies.¹ ¹ Knight’s Weekly, volume xvii., p. 64.