In June 1563 he obtained license to go to England on private business; but on 20 April 1563 he was again sent to Scotland with the special aim of entangling the Scottish queen in negotiations for an English marriage: In 1563, Elizabeth suggested Lord Robert Dudley, her own favourite, as a consort to Mary, whom she thus hoped to neutralise by a marriage to an Englishman. Ambassador Randolph tried his best to further the project, which was strongly advocated by Cecil, many of whose instructions to Randolph survive. At first Mary was not enthusiastic; however, when it became clear, that Elizabeth would declare Mary her official heir on condition that she marry Dudley, the proposal was taken very seriously on the Scottish part. In September 1564 Elizabeth bestowed on Dudley the earldom of Leicester to make him more acceptable to Mary. In the beginning of 1565, Mary accepted the proposal at last. To the amazement of Randfolph, however, Leicester was not to be moved to comply with the proposal: But a man of that nature I never found any...he whom I go about to make as happy as ever was any, to put him in possession of a kingdom, to make him Prince of a mighty people, to lay in his naked arms a most fair and worthy lady...nothing regardeth the good that shall ensue unto him thereby...but so uncertainly dealeth that I know not where to find him. Dudley indeed had made it clear to the Scots at the beginning of the affair, that he was not a candidate for Mary's hand, and forthwith had behaved with passive resistance. This Randolph had repeatedly tried to overcome by his letters. Elizabeth herself now had second thoughts regarding declarations concerning the succession. But as Henry Stuart, Lord Darnley became a serious candidate for Mary's marriage, Elizabeth wanted to prevent it. Randolph again received instructions to press for a marriage "with the Earl of Leicester or some other; and if he find it so far passed as it cannot be revoked, then he shall...declare, how much it shall miscontent her Majesty".