In the meantime, Rhodes rose to become the chief naval power in the Aegean and even beyond. In order to protect their political and commercial interests, such as the grain trade, where Rhodes held a dominant position, the Rhodians were active against pirates such as Demetrius of Pharos or the Cretan cities and the Aetolian League; both of the latter secretly sponsored by King Philip V of Macedon. By , according to Polybius ("The Histories", IV.47.1), the Rhodians "were considered the supreme authority in maritime matters" and were called upon by merchants to intervene in cases such as the imposition of tolls by the Byzantines on passage of ships through the Bosporus. In 201 BC, during the Cretan War, Philip V of Macedon subdued the Cyclades at the head of his fleet, but already in the next year, the Rhodians took over of most of the islands except for the Macedonian-garrisoned islands of Andros, Paros, and Kythnos. Followed by further Macedonian setbacks in the Second Macedonian War (200–197 BC), the Cycladic islands, already bound individually to Rhodes by treaties of alliance, were soon after—an exact date cannot be ascertained—formed into a "Second Nesiotic League" under the hegemony of Rhodes. The motivations for Rhodes' move are unclear, but the historian Kenneth Sheedy has suggested that they stemmed at least partly from a desire to preempt other powers, whether the Kingdom of Pergamon or the Roman Republic, from establishing control over the area. Unlike the original League however, the Second League appears to have been a more voluntary association. The Second Nesiotic League is commonly held to have lasted until the end of Rhodian independence at the conclusion of the Third Macedonian War in 167 BC, but Sheedy suggests that it may have started to disintegrate earlier, as the Rhodians focused their attention on maintaining their grip over their Asian holdings and could no longer afford to maintain the costly hegemony over the Cyclades.