This chapter looks at the specifically naval aspects of the operation, which would be repeated to even greater effect in the invasion of 1547. It focuses on the role of the newly appointed Lord Admiral, John Dudley, Viscount Lisle – best remembered as Duke of Northumberland in Edward VI’s reign, but whose work for the Royal Navy is properly credited. The 1544 campaign was essentially a punitive expedition, the context of which originated in Henry VIII’s desire to renew his alliance with the Emperor Charles V by making war on France. Because of his desire to exploit this golden opportunity, Henry’s preparations for a campaign in France were effectively derailed, much to the Emperor’s annoyance. There were rumours of French plans to intervene in the north, but for the time being it looked as though Arran would have time to sell the marriage in Scotland.