In spite of these successes the influence of the Whigs was gradually undermined by the intrigues of Charles Spencer, 3rd Earl of Sunderland, and by the discontent of the Hanoverian favourites. In October 1716, Townshend's colleague, James Stanhope afterwards 1st Earl Stanhope, accompanied the king on his visit to Hanover, and while there he was seduced from his allegiance to his fellow ministers by Sunderland, George being led to believe that Townshend and his brother-in-law, Sir Robert Walpole, were caballing with the Prince of Wales, their intention being that the prince should supplant his father on the throne. Consequently, in December 1716 the secretary was dismissed and was made Lord Lieutenant of Ireland, but he only retained this post until the following April. When he was dismissed for voting against the government, he was joined by his brother-in-law Robert Walpole and other Whig Allies. This began the Whig Split which would divide the dominant party until 1720, with the opposition Whigs joining with the Tories to defeat Stanhope's government over several issues including the Peerage Bill of 1719.