 Calvin and Servetus were first brought into contact in 1546 through a common acquaintance , Jean <unk> of Lyon ; they exchanged letters debating doctrine ; Calvin used a pseudonym as Charles d ' <unk> , while Servetus left his unsigned . Eventually , Calvin lost patience and refused to respond ; by this time Servetus had written around thirty letters to Calvin . Calvin was particularly outraged when Servetus sent him a copy of the Institutes of the Christian Religion heavily annotated with arguments pointing to errors in the book . When Servetus mentioned that he would come to Geneva , " <unk> " ( Calvin ) wrote a letter to Farel on 13 February 1546 noting that if Servetus were to come , he would not assure him safe conduct : " for if he came , as far as my authority goes , I would not let him leave alive . " 
