8. =The Treaty of Dover. 1670.=--Having secured a grant, Charles prorogued Parliament, which he had deceived by giving it to understand that he had abandoned the idea of toleration, and turned to Louis. Louis sent over Charles's youngest sister, Henrietta, Duchess of Orleans, to conclude an alliance, and on June 1, =1670=, a treaty between England and France was secretly signed at Dover. Charles agreed to join Louis in his projected war against the Dutch, by sending an English force of 6,000 men to serve in the French army, and to assist Louis to seize upon the territories of the Spanish monarchy in the event of the death of Charles II. of Spain without male heirs. Charles was also to acknowledge himself a Catholic whenever he thought fit to do so. To support Charles against his subjects in case of their resisting him in the declaration of his conversion, Louis was to give him 154,000_l._ and the aid of 6,000 troops to be employed in England in his defence. Moreover, Charles was to receive 230,000_l._ a year during the proposed war, and thirty French ships were to serve under an English admiral. At the end of the war he was to receive Walcheren, Sluys and Cadsand from the Dutch Republic, and ultimately, if Louis made good his claims to the Spanish monarchy, he was to gain from Spain, Ostend, Minorca, and various territories in South America. Charles II. was no more scrupulous than his father had been about using the troops of foreign princes to suppress the opposition of his own subjects, but he was shrewd enough to know--what Charles I. had never known--that foreign princes would not lend him troops unless he gave them something in return. The breach of the Triple Alliance and the assistance offered by Charles to Louis in the proposed war against the Dutch were considered in France to be a fair equivalent for the payments which Louis had bound himself to make. It was another question whether Charles could be kept to his engagements. To secure this as much as possible Louis sent him over a new French mistress, Louise de Keroualle. Charles soon created her Duchess of Portsmouth, and she fulfilled her duty to her own king by betraying to him all the secrets of her lover.