حنين بن إسحاق
Years before Ibn al-Nafis was born, Galenic physiology and anatomy dominated the Arabic medical tradition from the time of Hunayn ibn Ishaq (AD 809–873). Medical authorities at the time seldom challenged the underlying principles of this system. What set Al-Nafis apart as a physician was his boldness in challenging Galen's work. In studying yet criticizing the Galenic system, he formed his own medical hypotheses.