God bless you

For many; saying God Bless You after someone sneezes is a gesture of politeness. However the origin to such formality finds its roots in Pope Gregory the Great who would say it to people who sneezed during a bubonic plague; and from the erroneous belief that the soul escapes the body during a sneeze and the heart momentarily stops. Therefore saying God bless you was a way of welcoming the person back to life.