In 1733, Lord Chesterfield married Melusina von der Schulenberg, the Countess of Walsingham, who was the illegitimate daughter of the late King George I and his mistress, the Duchess of Kendal. After recuperating from his illness, Chesterfield resumed his seat in the House of Lords, of which he was now one of the acknowledged leaders. He supported the ministry and leadership of Robert Walpole, the de facto prime minister but withheld the blind fealty that Walpole preferred of his followers. Lord Chesterfield strongly opposed the Excise Bill, the Whig Party leader's favourite measure, in the House of Lords, and his brothers argued against it in the House of Commons. Even though Walpole eventually succumbed to the political fury and abandoned the measure, Chesterfield was summarily dismissed from his stewardship. For the next two years, he led the opposition in the Upper House to effect Walpole's downfall. During that time, he resided in Grosvenor Square and got involved in the creation of a new London charity called the Foundling Hospital for which he was a founding governor.