The reverse painting on glass method has been with us for centuries.  Some say Leonardo da Vinci suggested it so that light wouldn’t be scattered by a rough surface such as a canvas.  In  any case, this painting method known as hinterglas (German), sous verre (French and sotto verro (Italian) has been with us at least as long as painting on canvas.

Contrary to painting on a canvas or similar support this technique requires an artist to paint in reverse, or in other words, “back to front”.