In March 1536, Calvin published the first edition of his "Institutio Christianae Religionis" or "Institutes of the Christian Religion". The work was an "apologia" or defense of his faith and a statement of the doctrinal position of the reformers. He also intended it to serve as an elementary instruction book for anyone interested in the Christian faith. The book was the first expression of his theology. Calvin updated the work and published new editions throughout his life. Shortly after its publication, he left Basel for Ferrara, Italy, where he briefly served as secretary to Princess Renée of France. By June he was back in Paris with his brother Antoine, who was resolving their father's affairs. Following the Edict of Coucy, which gave a limited six-month period for heretics to reconcile with the Catholic faith, Calvin decided that there was no future for him in France. In August he set off for Strasbourg, a free imperial city of the Holy Roman Empire and a refuge for reformers. Due to military manoeuvres of imperial and French forces, he was forced to make a detour to the south, bringing him to Geneva. Calvin had intended to stay only a single night, but William Farel, a fellow French reformer residing in the city, implored him to stay and assist him in his work of reforming the church there. Calvin accepted his new role without any preconditions on his tasks or duties. The office to which he was initially assigned is unknown. He was eventually given the title of "reader", which most likely meant that he could give expository lectures on the Bible. Sometime in 1537 he was selected to be a "pastor" although he never received any pastoral consecration. For the first time, the lawyer-theologian took up pastoral duties such as baptisms, weddings, and church services.