But it was to the Duke of York that Churchill looked mainly for advancement, and he earned it by the fidelity with which as a member of his household he clung to the Duke's fortunes during the dark days of the Popish Plot. He followed James to Edinburgh and the Hague, and on his master's return he was rewarded with a peerage and the colonelcy of the Life Guards. The service he rendered James after his accession by saving the royal army from a surprise at Sedgemoor would have been yet more splendidly acknowledged but for the king's bigotry. In spite of his master's personal solicitations Churchill remained true to Protestantism. But he knew James too well to count on further favour after a formal refusal to abandon his faith. Luckily for him he had now found a new groundwork for his fortunes in the growing influence of his wife over the king's second daughter, Anne; and at the crisis of the Revolution the adhesion of Anne to the cause of Protestantism was of the highest value. No sentiment of gratitude to his older patron hindered Churchill from corresponding with the Prince of Orange, from promising Anne's sympathy to William's effort, or from deserting the ranks of the king's army when it faced William in the field. His desertion proved fatal to the royal cause; but great as this service was it was eclipsed by a second. It was by his wife's persuasion that Anne was induced to forsake her father and take refuge in Danby's camp. Unscrupulous as his conduct had been, the services which Churchill thus rendered to William were too great to miss their reward. On the new king's accession he became Earl of Marlborough; he was put at the head of a force during the Irish war where his rapid successes at once won William's regard; and he was given high command in the army of Flanders. [Sidenote: Churchill and William.]