17. =Oliver's Foreign Policy. 1654-1655.=--Partly, perhaps, because he hoped to divert attention from his difficulties at home, partly because he wished his country to be great in war as well as in peace, Oliver had for some time been engaging in naval enterprise. In the early part of his career he had been friendly to Spain, because France intrigued with the Presbyterians and the king. France and Spain were still at war, and when Cromwell became Protector he offered his alliance to Spain, on condition that Spain would help him to reconquer Calais, and would place Dunkirk in his hands as a pledge for the surrender of Calais after it had been taken. He also asked that commerce between England and her own West Indian colonies should be free from Spanish attacks, and for more open liberty of religion for the English in the Spanish dominions than had been offered by Spain in its treaty with Charles I. The Spanish ambassador replied that to ask these two things was to ask his master's two eyes, and plainly refused to admit an English garrison into Dunkirk. Upon this, Cromwell sent out, in the end of =1654=, two fleets, one--under Blake--to go to the Mediterranean, to get reparation from the pirates of Tunis and Algiers for wrongs done to English commerce; and the other--under Penn and Venables--to seize a Spanish island in the West Indies. Blake was successful, but Penn and Venables failed in an attempt on San Domingo, though they took possession of Jamaica, which at that time was not thought to be of much value. 18. =The French Alliance. 1655.=--As Oliver could not get what he wanted from Spain, he agreed to a treaty with France to end what had been virtually a maritime war, in which trading-ships had been seized on both sides. Freedom of religion was to be accorded to Englishmen in France. Before any treaty had been signed, news arrived that the Duke of Savoy had sent his soldiers to compel his Vaudois subjects to renounce their religion, which was now similar to that of the Protestants, though they had revolted from the Papacy long before Luther's Reformation. These soldiers committed terrible outrages amongst the peaceful mountaineers. Those who escaped the sword were carried off as prisoners, or fled to the snowy mountains, where they perished of cold and hunger. Milton's voice was raised to plead for them. "Avenge," he wrote-- "O Lord, thy slaughtered saints, whose bones Lie scattered on the Alpine mountains cold-- Even men who kept thy truth, so pure of old, When all our fathers worshipped stocks and stones." Cromwell at once told Mazarin that, if he cared for peace with England, this persecution must stop. Mazarin put pressure on the Duke of Savoy, and liberty of worship was secured to the Vaudois. Then, on October 24, =1655=, Oliver concluded the treaty with France.