In 1544 Howard accompanied the Earl of Hertford's forces in the invasion of Scotland. It was reported that he was hurt in the cheek by an English arrow during fighting on Edinburgh's Royal Mile. In July of that year he took part in the siege of Boulogne. On 27 May 1545 the King's Council ordered Howard to "repayre to serve uppon the sees". Later orders show that he detained several foreign vessels while patrolling the English Channel. In May 1546 he was entrusted with the sum of £12,000 to pay the English army at Calais. In connection with these duties he was referred to as "vice-admiral" to the then Lord Admiral, Viscount Lisle. When Lisle's attendance was required in May 1546 at negotiations which resulted in the signing of the Treaty of Ardres on 7 June 1546, he turned command of the English fleet over to Howard.