On September 29, 1509, Spanish theologian, physician, cartographer, and Renaissance humanist Michael Servetus was born. Servetus was a polymath versed in many sciences: mathematics, astronomy and meteorology, geography, human anatomy, medicine and pharmacology, as well as jurisprudence, translation, poetry and the scholarly study of the Bible in its original languages. He was probably the first European to correctly describe the function of pulmonary circulation.
Michael Servetus studied law in Toulouse. In 1531, he published his novel ideas on the Trinity in De Trinitatis erroribus libri vii. In his work, Servetus attacked the orthodox teaching and attempted to form a view of his own. One year later, he published an updated version titled Dialogorum de Trinitate libri ii. Then, after moving to Lyon under the name of Villanovanus, Servetus read and edited scientific works. He published a translation of Ptolemy’s Geographia. In the field of astrology, Michael Servetus published a work, discussing that the stars influenced health. In 1538, Servetus matriculated in medicine at Paris, despite attacks by the faculty, and subsequently became physician to the archbishop at Vienne, France. Servetus published his probably most important work, Biblia sacra ex Santis Pagnini tra[ns]latione in 1542, which was notable for its theory of prophecy.
In 1546, Michael Servetus forwarded the manuscript of an enlarged revision of his ideas, the Christianismi Restitutio, to Calvin, expressing the desire to meet him. However, after a few letters, it is believed that Calvin kept the manuscript and declared that if Servetus ever came to Geneva he would not allow him to leave alive. In 1553, a rewritten version of Servetus’ manuscript was secretly printed in 1,000 copies at Vienne. In it, Sertevus discussed the relationship between the Spirit and regeneration. Servetus also described as the first known European the discovery of the pulmonary circulation of blood. However, since in general Christianismi Restitutio was a theology work condemned by most of the Christian factions of his time, the discovery of pulmonary circulation remained mostly unknown until the dissections of William Harvey in 1616.
Guillaume de Trie got access to Michael Servetus’ letters to Calvin, and Servetus and his printers were exposed to the inquisitor general at Lyon. However, Servetus managed to escape during the trial and he later appeared ub Geneva. There, Michael Servetus was tried for heresy in 1553 and found guilty, mainly on his views of the Trinity and Baptism. In October, he was burned alive and his execution resulted in a Protestant controversy on imposing the death penalty for heresy, drew severe criticism upon John Calvin, and influenced Laelius Socinus, a founder of modern unitarian views.