THE centuries immediately following the disruption of the Roman empire witnessed the formation of the languages of southern Europe—Italian, Spanish, French—and the process of their building-up placed an almost insuperable barrier in the way of the advancement of learning. Latin became a dead language; Greek was entirely unknown; the spoken languages were never written. 'The whole treasury of knowledge was locked up from the eyes of the people.' All legal documents and all correspondence as well as all the rituals of the church were couched in Latin, and until the end of the thirteenth century it was very unusual for a layman to write or even to read. The clergy were the only clerks. It is disputed whether Charlemagne could sign his name, and it is certain that Alfred the Great had but an indifferent knowledge of Latin. From the sixth to the eleventh century the mass of the clergy were only slightly more enlightened. Alfred declares that at the date of his accession (871) he did not know a single priest south of the Thames who understood the ordinary prayers of the church, or who could translate Latin into his mother tongue. The ignorance of the dark ages in Europe is a direct consequence of the confusion of tongues.
Through the translations of Nestorian monks in the orient the works of Greek philosophers, physicians, mathematicians and astronomers became known to the Arabs in the eighth and ninth centuries. The precepts of Ptolemy were followed closely, even slavishly, by the astronomers of Bagdad, Persia, Egypt, Spain and Turkistan, so long as learning lasted in these lands. We owe an immense debt to the Arabs for their faithful transmission of astronomical theories which they had