The peace of Cambrai proved but a truce, and war between Charles and Francis repeatedly blazed forth. Francis made strange alliances in order to create all possible trouble for the emperor,--Scotland, Sweden, Denmark, the Ottoman Turks, even the rebellious Protestant princes within the empire. There were spasmodic campaigns between 1536 and 1538 and between 1542 and 1544, and after the death of Francis and the abdication of Charles, the former's son, Henry II (1547-1559), continued the conflict, newly begun in 1552, until the conclusion of the treaty of Cateau-Cambrésis in 1559, by which the Habsburgs retained their hold upon Italy, while France, by the occupation of the important bishoprics of Metz, Toul, and Verdun, extended her northeastern frontier, at the expense of the empire, toward the Rhine River. [Footnote: It was during this war that in 1558 the French captured Calais from the English, and thus put an end to English territorial holdings on the Continent. The English Queen Mary was the wife of Philip II of Spain.] [Sidenote: Results of the Wars between Charles V and Francis I] Indirectly, the long wars occasioned by the personal rivalry of Charles and Francis had other results than Habsburg predominance in Italy and French expansion towards the Rhine. They preserved a "balance of power" and prevented the incorporation of the French monarchy into an obsolescent empire. They rendered easier the rise of the Ottoman power in eastern Europe; and French alliance with the Turks gave French trade and enterprise a decided lead in the Levant. They also permitted the comparatively free growth of Protestantism in Germany. [Sidenote: The Turkish Peril] More sinister to Charles V than his wars with the French was the advance of the Ottoman Turks. Under their greatest sultan, Suleiman II, the Magnificent (1520-1566), a contemporary of Charles, the Turks were rapidly extending their sway. The Black Sea was practically a Turkish lake; and the whole Euphrates valley, with Bagdad, had fallen into the sultan's power, now established on the Persian Gulf and in control of all of the ancient trade-routes to the East. The northern coasts of Africa from Egypt to Algeria acknowledged the supremacy of Suleiman, whose sea power in the Mediterranean had become a factor to be reckoned with in European politics, threatening not only the islands but the great Christian countries of Italy and Spain. The Venetians were driven from the Morea and from the Ægean Islands; only Cyprus, Crete, and Malta survived in the Mediterranean as outposts of Christendom. [Sidenote: Suleiman the Magnificent]