where did bless you come from

The phrase "bless you" after someone sneezes comes from several historical and superstitious origins. One popular explanation dates back to the bubonic plague in Europe, when sneezing was a symptom often preceding death, and Pope Gregory I supposedly urged people to say "God bless you" as a prayer for protection. Another belief was that sneezing could expel a person's soul or open the body to evil spirits, so saying "bless you" was a protective blessing. Additionally, some thought the heart momentarily stopped during a sneeze and the phrase encouraged it to keep beating. Today, it is mostly a polite social custom with roots in these ancient ideas of blessing and protection.