Yet in some regards there is matter for surprise as to the works preserved.

Thus, as we have seen, the very extensive works of Aristotle on natural history, and the equally extensive natural history of Pliny, which were preserved throughout this period, and are still extant, make up relatively bulky volumes.

These works seem to have interested the monks of the Middle Ages, while many much more important scientific books were allowed to perish.

A considerable bulk of scientific literature was also preserved through the curious channels of Arabic and Armenian translations.
Reference has already been made to the Almagest of Ptolemy, which, as we have seen, was translated into Arabic, and which was at a later day brought by the Arabs into western Europe and (at the instance of Frederick II of Sicily) translated out of their language into mediaeval Latin.
It remains to inquire, however, through what channels the Greek works reached the Arabs themselves.

To gain an answer to this question we must follow the stream of history from its Roman course eastward to the new seat of the Roman empire in Byzantium.