He was very soon ready, and with his characteristic ardor and energy he determined on attempting to carry the city at once by assault. Fortified cities generally require a siege, and sometimes a very long siege, before they can be subdued. The army within, sheltered behind the parapets of the walls, and standing there in a position above that of their assailants, have such great advantages in the contest that a long time often elapses before they can be compelled to surrender. The besiegers have to invest the city on all sides to cut off all supplies of provisions, and then, in those days, they had to construct engines to make a breach somewhere in the walls, through which an assaulting party could attempt to force their way in.