Shortly after the embassy of von Zara and Schepper, Suleiman left Europe to wage war against the Persians. As usual when planning a campaign in one direction, he made careful arrangements to keep matters quiet on other frontiers. He treated in secret with Francis I, agreeing to despatch Barbarosa with a fleet to ravage the coasts of the Empire; this was a great success for French diplomacy, for the advantage was all in favor of France. Then, fearing lest the rivals for the Hungarian throne should come to an agreement in his absence, and thus menace his suzerainty, Suleiman delegated Luigi Gritti to determine the frontiers between the possessions of the two kings. This was a clever move, for it prolonged the intrigues between the royal competitors until the return of the sultan. The successes of Barbarosa, the victories and defeats of Charles V on the Mediterranean, and the continuation of French diplomacy are outside the limits of our subject, which ends with the death of Ibrahim Pasha in 1535. Gévay preserves several letters written by Ferdinand to Ibrahim in 1535–6, in the interest of peace in Hungary, the last being dated March 14, 1536, a year after Ibrahim’s death. The last international act in which Ibrahim Pasha had a part was the celebrated treaty of commerce made with France in February, 1535. Francis I had received a Turkish mission, not from the haughty Sultan, but from his admiral Barbarosa,[117] and in return the king sent a clever diplomat named La Forest, to thank Barbarosa for his kind offers of aid, and then to seek the sultan in Persia and conclude a definite treaty with him.[118] Suleiman received La Forest in his military camp, keeping him till his own return to Turkey in 1535. The treaty is dated February, 1535; it formed the basis of the economic, religious, and political protectorate of France in the Levant. The French might carry on commerce in the Levant by paying the same dues as did the subjects of the Sultan, and the Turks could do the same in France. The French were to be judged by their consul at Alexandria or by their ambassador at Constantinople. This treaty ended the commercial predominance of Venice in the Mediterranean. After this, all Christians except the Venetians were forced to put themselves under the protection of the French flag, which alone guaranteed inviolability.[119] This commercial freedom and political influence gained by France involved a sort of economic protection and was supplemented by a religious protectorate over the Catholics in the Levant and the Holy Places. After this sketch of the beginnings of diplomatic relations between the Porte and the two rival powers of Europe, the House of Hapsburg and the House of Valois, we are ready to consider the significance of these relations and to take up some of the details that will serve to bring out the share of Ibrahim Pasha in Turkish diplomacy, and his characteristics as a diplomat.