Of all the Slavonic tribes settled in Dalmatia, the most lawless and uncivilised were the Narentans, the Arentani or Porphyrogenitus. This hardy race of mariners occupied the land about the mouth of the Narenta[38] and the coast,[39] between that river and the Četina, besides the islands of Brazza, Lesina, Curzola, Lissa, Meleda, and Lagosta. Connected by racial ties with the Serbs and the Croatians, they obeyed the laws of neither. The ancient Illyrians were famous for their piracy, which first called the attention of the Romans to the country, and the Narentans proved worthy successors of the aborigines. The conformation of the coast with its numerous inlets, well-sheltered harbours, safe refuges, and countless islands lends itself to this species of occupation. The Narentans ravaged the coast towns of Dalmatia with their swift galleys, plundered peaceful merchantmen, and so harried Venetian trade that the Republic was forced to pay them blackmail for a hundred and fifty years. On more than one occasion it sent its fleets to attempt their subjugation, at first with but little success. At the beginning of these wars Ragusa was a friendly harbour for the Venetian galleys, their most southern port of call in the Adriatic, where they could revictual and their crews rest from the fatigues of the voyage.[40] But the Ragusans very soon began to look askance at the Venetians as a possible danger to their own independence, and adopted the practice of secretly, or even openly, supporting the pirates against the Venetians. This naturally caused trouble later when the Venetians were strong enough to act energetically against the Narentans: it affords a curious insight into the policy of the Ragusans, who, while anxious to preserve their own civilisation and culture, were never averse to siding with barbarians, whether they were Narentans or Turks, against Christian Powers, especially against Venice. As early as the reign of the Doge Giovanni Particiaco I. (829-836) the pirates of the Narenta had begun to seize Venetian galleys, and his successor, Pietro Tradonico (836-864), sent two punitive expeditions against them without definite result. After the Venetian fleet had been defeated by the Saracens, the Dalmatian corsairs were audacious enough to make a raid on the Lagoons. In 887 the Doge Pietro Candiano I. sent a first unsuccessful expedition against them, and a few months later led a second himself. This too was defeated, and the Doge killed. Probably there was another in 948 under Pietro Candiano III., and this time operations were directed against Ragusa itself, if we are to believe the native historians, the town being saved only through the special intercession of San Biagio,[41] who henceforth became the patron of Ragusa in the place of San Bacco.[42]