Reluctant as the liberal men were, to take a denominational position, and to commit themselves to the interests of a party in religion, or even to withdraw themselves in any way from the churches with which they had been connected, they were compelled to do so by the force of conditions they could not control. One of the first distinct lines of separation was caused by the refusal of the more conservative men to exchange pulpits with their liberal neighbors. This tendency first began to show itself about the year 1810; and it received a decided impetus from the attitude taken by Rev. John Codman, who in 1808 became the minister of the Second Church in Dorchester. He refused to exchange with several of the liberal ministers of the Boston Association, although he was an intimate friend of Dr. Channing, who had directed his theological training, and also preached his ordination sermon. The more liberal members of his parish attempted to compel him to exchange with the Boston ministers without regard to theological beliefs; and a long contention followed, with the result that the more liberal part of his congregation withdrew in 1813, and formed the Third Religious Society in Dorchester.[9] The withdrawal of ministerial courtesies of this kind gradually increased, especially after the controversies that began in 1815, though it was not until many years later that exchanges between the two parties ceased. In 1815 Dr. Jedidiah Morse, the editor of The Panoplist, and the author of various school books in geography and history, published in a little book of about one hundred pages, which bore the title of American Unitarianism, a chapter from Thomas Belsham's[10] biography of Theophilus Lindsey, in which Dr. Lindsey's American correspondents, including prominent ministers in Boston and other parts of New England, had declared their Unitarianism. Morse also published an article in The Panoplist, setting forth that these ministers had not the courage of their convictions, that, while they were Unitarians, they had withheld their opinions from open utterance. His object was to force them to declare themselves, and either to retract their heresies or else to state them and to withdraw from the churches with which they had been connected. In a letter addressed to Rev. Samuel C. Thacher, Dr. Channing gave to the public a reply to these charges of insincerity and want of open-mindedness. He said that, while many of the ministers and members of their congregations were Unitarians, they did not accept Dr. Belsham's type of Unitarianism, which made Christ a man. He declared that no open declaration of Unitarianism had been made, because they were not in love with the sectarian spirit, and because they were quite unwilling to indulge in any form of proselyting. "Accustomed as we are," he wrote, "to see genuine piety in all classes of Christians, in Trinitarians and Unitarians, in Calvinists and Arminians, in Episcopalians, Methodists,