 The middle years of his career mark his greatest philosophical contributions, beginning with the Boyle lectures (delivered 1704 and 1705). The first, an attempt to prove the existence of God, along with all divine attributes, was published as A Demonstration of the Being and Attributes of God (1705) and the second, a continuation intended to establish all fundamental moral truths and most religious doctrine, as A discourse concerning the unchangeable obligations of natural religion, and the truth and certainty of the Christian revelation (1706). They both went through many editions and were often published together. These lectures, established by Robert Boyle to promote natural religion based on the latest scientific developments, were closely watched, and Clarke instantly became one of the most well known philosophers in England. Also in 1706, his association with Newton became official when he translated the Opticks into Latin. In the meantime, he had been introduced to Queen Anne, who made him one of her chaplains in 1706, and three years later he was elevated to the rectory of St. James’s, Westminster. After the Hanoverian accession, Clarke developed a close relationship with Caroline of Ansbach, the Princess of Wales and future queen. His prominence as a philosopher drew him into a series of very public exchanges of letters. The most notable of these were the letters to Anthony Collins (1707–1708) and the letters to Leibniz (1715–1716) (see below).