Particular lamps made from timbers, which people used to raise above the level of the walls and signal to their neighbours or their allies, when they see an enemy approaching, that it is necessary to ward them off. They used to do this with regard not only to enemies but friends also: when they saw help coming they would signal again, by means of the beacons, that there was no need for alarm. And when they were displaying [a message about] friends they used to raise the beacons and hold them still; but whenever [it was about] enemies, they would move them.