ʿAlāʾ al-Dīn Abū al-Ḥasan ʿAlī ibn Abī Ḥazm al-Qarashī al-Dimashqī (Arabic: علاء الدين أبو الحسن عليّ بن أبي حزم القرشي الدمشقي), known as Ibn al-Nafīs (Arabic: ابن النفيس), was an Arab polymath whose areas of work included medicine, surgery, physiology, anatomy, biology, Islamic studies, jurisprudence, and philosophy. He is known for being the first to describe the pulmonary circulation of the blood. The work of Ibn al-Nafis regarding the right sided (pulmonary) circulation pre-dates the later work (1628) of William Harvey's De motu cordis. Both theories attempt to explain circulation. 2nd century Greek physician Galen's theory about the physiology of the circulatory system remained unchallenged until the works of Ibn al-Nafis, for which he has been described as "the father of circulatory physiology". As an early anatomist, Ibn al-Nafis also performed several human dissections during the course of his work, making several important discoveries in the fields of physiology and anatomy. Besides his famous discovery of the pulmonary circulation, he also gave an early insight of the coronary and capillary circulations. He was also appointed as the chief physician at al-Naseri Hospital founded by Sultan Saladin. Apart from medicine, Ibn al-Nafis studied jurisprudence, literature and theology. He was an expert on the Shafi'i school of jurisprudence and an expert physician. The number of medical textbooks written by Ibn al-Nafis is estimated at more than 110 volumes. Biography Ibn al-Nafis was born in 1213 to an Arab family probably at a village near Damascus named Karashia, after which his Nisba might be derived. Early in his life, he studied theology, philosophy and literature. Then, at the age of 16, he started studying medicine for more than ten years at the Nuri Hospital in Damascus, which was founded by the Turkish Prince Nur-al Din Muhmud ibn Zanki, in the 12th century. He was contemporary with the famous Damascene physician Ibn Abi Usaibia and they both were taught by the founder of a medical school in Damascus, Al-Dakhwar. Ibn Abi Usaibia does not mention Ibn al-Nafis at all in his biographical dictionary "Lives of the Physicians". The seemingly intentional omission could be due to personal animosity or maybe rivalry between the two physicians. In 1236, Ibn al-Nafis, along with some of his colleagues, moved to Egypt under the request of the Ayyubid sultan al-Kamil. Ibn al-Nafis was appointed as the chief physician at al-Naseri hospital which was founded by Saladin, where he taught