It is generally thought that the physicist William Harvey (England) discovered the circulation of blood in 1628. In fact, a 13th-century Arab physician, Ibn al-Nafis al-Quarashi, had already mentioned the existence of pulmonary circulation in a work dedicated to the Persian philosopher and scientist Ibn Sina or Avicenna. This work passed unnoticed until it was referred to in 1552 by theologian and physician Miguel Serveto (Spain) in his theological and medical work, Restitutio Christianismi, for which he was burned at the stake.
From 1550 onwards, several physiologists of the Paduan school, including Matteo Colombo, Carpi and Hieronymus Fabricius of Aquapendente, studied the problem. William Harvey based his work on that of his predecessors and had the inspired idea of considering the heart as a pump that was operated by muscular pressure. Proof of the existence of capillary vessels linking the arterial and venous systems was supplied in 1661 by the anatomist Marcello Malpighi (Italy). (Inventions and Discoveries)