"Bless You"

Why?Why are these words spoken?

  Some people believed that a sneeze causes the soul to escape the body through the nose. Saying "bless you" would stop the devil from claiming the person's freed soul. There was also the misconception that the heart momentarily stops during a sneeze (it doesn't), and that saying "bless you" was a way of welcoming the person back to life.

When? When did this saying originated?

The sixths century?

How? How did this saying originated?

The phrase "God bless you" is attributed to Pope Gregory the Great, who uttered it in the sixth century during a bubonic plague epidemic

Where? Where did this saying originated? 

Germany or from ancient superstitions