In the shadow of the sword

No less significant than the collapse of the Roman Republic or the Persian invasion of Greece, the evolution of the Arab empire is one of the supreme narratives of ancient history, a story dazzlingly rich in drama, character, and achievement. Just like the Romans, the Arabs came from nowhere to carve out a stupefyingly vast dominion?except that they achieved their conquests not over the course of centuries as the Romans did but in a matter of decades. Just like the Greeks during the Persian wars, they overcame seemingly insuperable odds to emerge triumphant against the greatest empire of the day?not by standing on the defensive, however, but by hurling themselves against all who lay in their path.