It sounded like fireworks.  Like when you are young and wake early to the sound of them testing the big rockets, and when you look out the window the sky is clear and blue and thick white plumes are drifting across the fields.  Only this was very long ago, before the Chinese had begun sending 'powdered dragons' off along the camel routes, before, even, those days when bejeweled Carthaginian elephants were heard to fall, trumpeting, through the dazzling alpine air, so that the sounds, when they came, came without remembered precedent, although the Sibyl whom they consulted, said that sounds like those had often knocked the doors off their hinges in her dreams.