The Justinian Plague, which began in 541 A.D., is so called because it took place while Justinian I (c. 482-565) was emperor of the Byzantine Empire. It is said to have killed up to 5,000 people a day, or 25 million people worldwide. An early symptom of the plague was sneezing. by saying "God bless you," people hopes that the disease could be halted in the one who had sneezed.
- Little Black Book, Diocese of Saginaw