On October 27th 1553, the physician and religious reformer Miguel Servet was burnt at stake. The 450th anniversary of his death took place, therefore, a few months ago. This is a fact which deserves being taken into account, not only because of the importance of the individual, but also, and mainly, because during the last years some important historiographical advances have changed the traditional approach, giving place to a new and more accurate analysis to his life and work. The topic image of Servet spread by the Spanish historiography of the 19th and most of the 20th Centuries has been that of a scientific genius, discoverer of the pulmonary circulation of blood, but also that of a crazy theologian with absurd ideas about some basic Christian dogmas, specially the Holy Trinity. This image is now considered absolutely misleading. The historiography of the complex religious movements of the 16th Century has shown that Servet, far from being a crazy theologian absolutely disconnected of the religious movements of the Century, was instead one of the leaders of an important Christian movement which G. H. Williams called <<the radical reformation.>> He consecrated all his life to this goal, which also was the reason of his death, always showing an absolute and admirable intellectual and human coherence. To these goals he subdued any other objective, as well as the study and the exercise of medicine. This gives the basis to correctly understand the fact, never explained convincingly until now, why his great scientific discovery, the pulmonary circulation of blood, appeared as a minimal part in the heart of a theological book.