In one of their meetings Haro wore in his hat, as an ornament, a medal impressed with the portrait of the Infanta Maria Theresa, Philip’s daughter by his first wife. ‘If your King would give to my master for a wife the original of the portrait you wear,’ said Lionne, duly instructed by Mazarin, ‘peace would soon be made.’ Nothing more was said at the time, for, in the absence of a son, Philip dared not marry the heiress of Spain to his nephew Louis XIV., but when an heir was born to Mariana, the idea of a marriage between Maria Theresa and Louis XIV. at once became realisable. The Austrian interest still stood in the way; and Mariana, who was as purely an ambassador for her brother as his accredited diplomatic representative was, used all her efforts to frustrate the plan; and a marriage was actively advocated by her between the Infanta and Leopold, the heir of the empire. Philip for a long time allowed himself to incline to the Austrian connection that had already cost him so dear. As soon as the French match looked promising, as a result of much secret intrigue between Mazarin and Haro, the Emperor offered to Philip a great army in Flanders to aid in expelling the French; and when Philip was hesitating between the persuasions of his wife Mariana, and her kinsmen on the one hand, and the pressure of poverty on the other, which made a continuance of the war difficult for him, Mazarin played a trump card which won the game. Louis was taken ostentatiously to Lyons to woo the Princess of Savoy; and, in fear of a coalition against Spain, Philip sent his minister Haro to negotiate peace with Mazarin personally on the banks of the Bidasoa. During all the autumn of 1659, on the historic Isle of Pheasants in the river, the keen diplomatists fought over details; and often their labours seemed hopeless, for the Spaniards were as proud as ever and the French as greedy. But the frail health of the puling babe, who alone stood between the Infanta and the Spanish succession, at length made Mazarin more yielding: the last great obstacle, the restoration of Condé’s forfeited estates, was overcome, and one of the most fateful treaties in history was settled.