In 1761 he became personally known to Pitt, who, recognizing his ability and discretion, once and again made use of his services as private amanuensis. In 1762 he was appointed to a principal clerkship in the war office, where he formed an intimate friendship with Christopher D'Oyly, the secretary of state's deputy, whose dismissal from office in 1772 was hotly resented by "Junius"; and in the same year he married Miss Macrabie, the daughter of a retired London merchant. His official duties brought him into direct relations with many who were well versed in the politics of the time. In 1763 the great constitutional questions arising out of the arrest of Wilkes began to be sharply canvassed. It was natural that Francis, who from a very early age had been in the habit of writing occasionally to the newspapers, should be eager to take an active part in the discussion, though his position as a government official made it necessary that his intervention should be carefully disguised. He is known to have written to the _Public Ledger_ and _Public Advertiser_, as an advocate of the popular cause, on many occasions about and after the year 1763; he frequently attended debates in both Houses of Parliament, especially when American questions were being discussed; and between 1769 and 1771 he is also known to have been favourable to the scheme for the overthrow of the Grafton government and afterwards of that of Lord North, and for persuading or forcing Lord Chatham into power. In January 1769 the first of the _Letters of Junius_ appeared, and the series was continued till January 21, 1772. They had been preceded by others under various signatures such as, "Candor," "Father of Candor," "Anti-Sejanus," "Lucius," "Nemesis," which have all been attributed, some of them certainly in error, to one and the same hand. The authorship of the _Letters of Junius_ has been assigned to Francis on a variety of grounds (see JUNIUS).