Alone among the barbarian peoples who lurked beyond the borders of the Roman Empire, they featured in it. Isaac, so it was recorded in Genesis, had not been Abraham’s only son. The patriarch had also fathered a second, Ishmael, on an Egyptian slave. This meant that the Arabs – whom commentators had long since identified with the descendants of Ishmael – could claim a lineal descent from the first man to reject idolatry.
