century was Boethius translation of the Categories and De Emendatione. Thus Aristotle was
conceived as a mere dialectician, and Plato as only a religious philosopher and the author of the
theory of ideas. During the course of the later Middle Ages, both these partial conceptions were
gradually emended, especially the conception of Aristotle. But the process, as regards Plato,
was not completed until the Renaissance.
CHAPTER X Mohammedan Culture and PhilosophyTHE attacks upon the Eastern Empire, Africa, and Spain differed from those of Northern
barbarians on the West in two respects: first, the Eastern Empire survived till 1453, nearly a
thousand years longer than the Western; second, the main attacks upon the Eastern Empire were
made by Mohammedans, who did not become Christians after conquest, but developed an
important civilization of their own.
The Hegira, * with which the Mohammedan era begins, took place in A.D. 622; Mahomet died
ten years later. Immediately after his death the Arab conquests began, and they proceeded with
extraordinary rapidity. In the East, Syria was invaded in 634, and completely subdued within
two years. In 637 Persia was invaded; in 650 its conquest was completed. India was invaded in
664; Constantinople was besieged in 669 (and again in 716-17). The westward movement was
not quite so sudden. Egypt was conquered by 642, Carthage not till 697. Spain, except for a
small corner in the north-west, was acquired in 711-12. Westward expansion (except in Sicily
and Southern Italy) was brought to a standstill by the defeat of the Mohammedans at the battle
of Tours in 732, just one hundred years after the death of the
* The Hegira was Mahomet's flight from Mecca to Medina.