when he did sleep , he fell straight into nightmares ; not the kind that had you wake with a sudden lurch , your heart beating fast , but more insidious nightmares in which he wandered the streets of rome with a companion , but when he turned , his companion had disappeared , and the streets were empty ; or one in which he stood alone in a huge temple , lit only by a single brazier by which he stood , and which was dying , the darkness gathering in the corners of the great cella , and voices of dead cities whispering from the dark .