Lucretius

From De Rerum Natura (On the Nature of Things), by Lucretius (c.99-55 BC):

. . .I now begin

To teach you about images, so- called

A subject of most relevant importance.

These images are like a skin, a film,

Peeled from the body's surface, and they fly

This way and that across the air; they cause

A terror in our minds, whether we wake

Or in our sleep see fearful presences.

The replicas of those who have left the light

Haunt us and startle us horribly in dreams.

Let me repeat: these images of things,

These almost airy substances, are drawn

From surfaces; you might call them film, or bark,

Something like skin, that keeps the lock, the shape

Of what it held before its wandering.