For a time, however, there were no European complications of a formidable nature. In 1816 a British squadron was sent out under Lord Exmouth lo execute the decree of the congress of Vienna against the Barbary states. The Dey of Algiers and the Beys of Tunis and Tripoli were called upon to recognise the Ionian Islands as British, to accept British mediation between them and the courts of the Two Sicilies and Sardinia, to restore their Christian captives, and not to authorise further piracy. These terms were accepted by the Beys of Tunis and Tripoli, and the two first demands were granted by the Dey of Algiers. He was allowed a delay of three months in order to obtain the sultan's permission for granting the remainder, but in the interval a massacre of Italian fishermen took place at Bona. Lord Exmouth now sailed from Gibraltar to attack Algiers. On his demands being again ignored, he bombarded that city on August 27 for more than six hours. The arsenal and storehouses and all the ships in the port were burned, and on the next day the dey accepted Exmouth's terms; peace was signed on the 30th, the principal terms being the abolition of Christian slavery, and the delivery of all slaves to Exmouth on the following day. The treaty of Vienna in placing the Ionian Islands under British protection had made no mention of the towns of Parga and Butrinto on the mainland of Epirus which had passed under British rule along with the islands. These places were now surrendered to Turkey in accordance with a former treaty, in return for the Turkish recognition of the British protectorate over the islands. The inhabitants of Parga were, however, vehemently opposed to such a transference of their allegiance, and they were conveyed to the Ionian Islands and compensated for the loss of their property. The Turks entered into occupation of Parga in 1819. In 1817 and 1818 wild rumours of Russian aggression in the direction of the Mediterranean began to circulate in England. It was reported that Spain had promised to cede Port Mahon to Russia; and that Russia was preparing a great military force, to be employed, if necessary, in alliance with the Bourbon states, France, Spain, and the Two Sicilies, to counteract British and Austrian influence. This influence, with that of Prussia, had really been employed to keep the Dardanelles closed against Russian ships. Meanwhile Austria had won over Prussia to her conservative policy in Germany.