information:highlighting, quality:correction, linguistic:voice_change, structural:reformatting, information:extraction
Religion and health

Her tutor, Johannes Matthiae, influenced by John Dury and Comenius, who since 1638 had been working on a new Swedish school system, represented a gentler attitude than most Lutherans. In 1644, he suggested a new church order, but it was voted down as this was interpreted as Crypto-Calvinism. Queen Christina defended him against the advice of Chancellor Oxenstierna, but three years later, the proposal had to be withdrawn. In 1647, the clergy wanted to introduce the Book of Concord (Swedish: Konkordieboken) – a book defining correct Lutheranism versus heresy, making some aspects of free theological thinking impossible. Matthiae was strongly opposed to this and was again backed by Christina. The Book of Concord was not introduced.

In 1651, after reigning for almost twenty years, working at least ten hours a day, Christina had a nervous breakdown or burn out. For an hour, she seemed to be dead. She suffered from high blood pressure and complained about bad eyesight and her crooked back. She had already seen many court physicians. In February 1652, the French doctor Pierre Bourdelot arrived in Stockholm. Unlike most doctors of that time, he held no faith in blood-letting; instead, he ordered sufficient sleep, warm baths, and healthy meals, in contrast to Christina's hitherto ascetic way of life. She was only twenty-five; and advising that she should take more pleasure in life, Bourdelot asked her to stop studying and working so hard and to remove the books from her apartments.

For years, Christina knew by heart all the poems from the Ars Amatoria and was keen on the works by Martial and Petronius. The physician showed her the 16 erotic sonnets of Pietro Aretino, which he kept secretly in his luggage. By subtle means, Bourdelot undermined her principles. Having been Stoic, she now became an Epicurean. Her mother and de la Gardie were very much against the activities of Bourdelot and tried to convince her to change her attitude towards him; Bourdelot returned to France in 1653 "laden in riches and curses".

The Queen had long conversations about Copernicus, Tycho Brahe, Francis Bacon, and Kepler with Antonio Macedo, secretary and interpreter for Portugal's ambassador. Macedo was a Jesuit, and in August 1651, smuggled on his person a letter from Christina to his general in Rome. In reply, Paolo Casati and Francesco Malines, trained in both natural sciences and theology, came to Sweden in the spring of 1652. She had more conversations with them, being interested in Catholic views on sin, the immortality of the soul, rationality, and free will. The two scholars revealed her plans to Cardinal Fabio Chigi. Around May 1652 Christina, raised in the Lutheran Church of Sweden, decided to become Catholic. She sent Matthias Palbitzki to Madrid and King Philip IV of Spain sent the diplomat Antonio Pimentel de Prado to Stockholm in August.