Muhammad ibn Zakariya al-Razi
Measles is an old disease, but it was not until the 10th century that the Persian physician Muhammad ibn Zakariya al-Razi (865–925) – known as "Rhazes" – first identified it. Rhazes used the Arabic name "hasbah" (حصبة) for measles. It has had many other names including "rubeola" from the Latin word "rubeus", "red", and "morbilli", "small plague". The close similarities between measles virus, canine distemper virus and rinderpest virus have given rise to speculation that measles was first transmitted to humans from domesticated dogs or cattle. The measles virus appears to have fully diverged from the then-widespread rinderpest virus by the 12th century.