The king came to view him more favourably as he defended the Newcastle ministry in the House of Commons. He was promoted major-general on 18 March 1755, and was at last made Colonel of the Blues on 27 May 1758. On 21 August, Granby arrived at Munster as second in command to Lord George Sackville, as the aged Duke of Marlborough had recently died. The British cavalry were divided into Heavy and Light cavalry and drilled under the strong influence of George Elliot and Granby himself. Accredited as the greatest colonel since the Earl of Oxford, Granby was both courageous and competent as a soldier. He was then appointed overall commander of the expedition, replacing Sackville on 21 August 1759. He became Lieutenant-General of the Ordnance on 15 September 1759.