The opening of Philip’s reign was marked by signal military successes. War broke out afresh with France, after a brief truce, in 1557. The French arms however sustained two crushing reverses at St Quentin, August 10, 1557, and at Gravelines, July 13, 1558. Lamoral, Count of Egmont, who commanded the cavalry, was the chief agent in winning these victories. By the treaty of Cateau-Cambresis peace was concluded, in which the French made many concessions, but were allowed to retain, at the cost of Philip’s ally, the town of Calais which had been captured from the English by a surprise attack in 1558. By the death of Queen Mary, which was said to have been hastened by the news of the loss of Calais, Philip’s relations with England were entirely changed, and one of the reasons for a continuance of his residence in the Netherlands was removed. Peace with France therefore was no sooner assured than Philip determined to return to Spain, where his presence was required. He chose his half-sister Margaret, Duchess of Parma, to be regent in place of the Duke of Savoy. In July he summoned the Chapter of the Order of the Golden Fleece—destined to be the last that was ever held—to Ghent in order to announce his intended departure. A little later the States-General were called together, also at Ghent, for a solemn leave-taking. On August 26, Philip embarked at Flushing, and quitted the Netherlands, never again to return.